SARASWATI STUDY POINT
Carbon & it’s Compounds
1.
2.
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33.
What is the term used for the compounds which have same molecular formula but different structures.
Why are saturated hydrocarbons more reactive than unsaturated hydrocarbons?
What is meant by a functional group?
Name the type of bond formed between two non-metals.
What is the reactive site in the hydrocarbon H3 C – CH2 – CH = CH – CH3.
How many valence electrons are there in valence shell of carbon atom?
Define catenation.
Name the cyclic unsaturated hydrocarbon containing three double bonds.
What is scum?
Write the colour of flame produced by unsaturated hydrocarbons on complete combustion?
What is the difference in number of carbon and hydrogen atoms between two successive numbers of a
homologous series?
Why acetic acid is known as glacial acetic acid?
In your science laboratory, how will you convert soft water into hard water?
What are detergents?
Name the functional group present in the following compounds:(i) C2 H5 OH
(ii) CH3 CO C2 H5
Name the type of hydrocarbon taking part in an addition reaction.
The molecular mass of two hydrocarbons A and B are 16u and 44u respectively. Do they belong to same
homologous series?
What is the difference in molecular masses of any two successive homologous?
Name the gas evolved when sodium carbonate or bicarbonate reacts with ethanoic acid.
Substitution reactions are given by which type of hydrocarbons?
Name the products obtained from the complete combustion of saturated hydrocarbon.
Name the catalysts commonly used in the process of vegetable oils into fats.
Which type of flame is produced by saturated hydrocarbons on incomplete combustion?
Draw electron dot structure for H2, O2, H2O and CH4.
Which hydrocarbons from the following undergoes additions reactions; why
C2, H6, C2 H2, C3 H8, C3 H6.
Write the two factors because of which carbon compounds exists in large numbers.
Explain why saturated hydrocarbon gives nonsooty clear flame on the complete combustion?
Differentiate between saturated and unsaturated hydrocarbons giving one example of each.
Write the chemical formula and structural formula of:(i) Benzene
(ii) Propanoic acid
What are structural isomers? Illustrate possible isomers of Butane (C4H10).
What is hydrogenation? Write its industrial application.
Write name of the following compounds as per nomenclature:(i) CH3 CH2 COOH
(ii) CH3 CH2 C ≡ CH
Name the functional group and select one hetro atom present in the following compounds:(i) C4 H9 Br
(ii) CH3 COC2 H5
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34. What is hydrocarbon? Write the general formula of the hydrocarbons:(i) Alkane
(ii) Alkene
(iii) Alkyne
35. Write an activity to show the acidic nature of ethanol. Give the chemical equation of the reaction taking
place.
36. Write the common nature of ethanoic acid. What is its dilute solution (5-8%) in water known as?
37. A, B and C are members of a homologous series, melting point are -183ºC, -138ºC and -130ºC
respectively.
Among these:(i) Which member will have least number of carbon atoms?
(ii) Which member will have maximum number of carbon atoms?
38. A hydrocarbon compound A is active ingredient of wine and cough syrups. A on oxidation with acidified
Cr2O7 forms compound B. Identify the compound A and B and write the chemical equations involved.
39. Which type of reactions takes place when saturated hydrocarbons react with chlorine in presence of
sunlight? Write the chemical equation if the saturated hydrocarbon is methane (CH4).
40. Draw the structural isomers of pentane.
41. Explain the following terms with related chemical equations:(i) Dehydration
(ii) Esterification
(iii) Saponification
42. Write the chemical formula and structure of the following:(i) Cyclohexane
(ii) Propanal
(iii) Chlorobutane
43. Explain formation of micelles with the help of suitable diagram:44. Draw the electron dot structure of the following:- (i) C2 H6
(ii) C2 H4
(iii) C2 H2
45. Write the chemical equations for the following chemical reactions:(i) Conversion of oils (unsaturated hydrocarbon) into fats (saturated hydrocarbon)
(ii) Oxidation of ethanol with alkaline potassium permanganate
46. How would you name the following compounds:(i) CH3 – CH2 – CH2 – Cl.
(ii) CH3 CHO
(iii) CH3 CH2 CH = CH2.
47. Write its homologous series? Write the homologous series of alloy upto four carbon atoms.
48. Write three differences between soap and detergents.
49. What are soaps? Explain the mechanism of the cleaning action of soaps? Soaps form Scum (insoluble
substance) with hard water. Explain why? How this problem is overcome by the use of detergents?
50. Differentiate between ethanol and ethanoic acid on basis of following test:(i) Blue litmus
(ii) Reaction with sodium bicarbonate
(iii) Sodium metal test
51. How can you obtain the following from pure ethanol:- (i) Ethene
(ii) Ethanoic acid
(iii) Ester
Write the chemical equation of the reaction.
52. Giving chemical equation of the reactions write what happens when:(i) Ethanol is heated with excess of concentrated sulphuric acid at 44.3k.
(ii) Ethanoic acid reacts with ethanol in presence of an acid.
(iii) Ester, with molecular formula CH3 COO C2 H5, reacts with sodium hydroxide.
53. A hydrocarbon X having molecular formula C2 H4O2 reacts with sodium bicarbonate gives a compound Y
with water and an effervescence which turns lime water milky. Compound X reacts with ethanol in presence
of concentrated sulphuric acid to form a sweet smelling substance Z which is used in making perfumes.
(i) Identify the compound X,Y and Z.
(ii) Write the balanced chemical equation to present the conversion of:(a) Compound X to Compound Y and
(b) Compound X to Compound Z.
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54. Identify the compound A, B, C, D and E in the following chemical reactions:(i) CH3 CH2 OH + A → A
(ii) CH3 CH2 OH + A → B + H2O
(iii) B + NaOH → O2H5OH + C
(iv) O + Na2CO3 → CH3COONa + D + H2O
(v) D + Ca(OH)2 → E + H2O
Answer these questions:1.
2.
3.
4.
5.
6.
7.
What is the name and chemical formula of acetic acid?
Write the formulation for the functional groups of alcohols and carboxylic acids.
Write (i) the name and (ii) Formula of the functional group present in the compound, CH3COOH.
How are the molecules of aldehydes & ketones structurally different?
Write the name and chemical formula of the organic compounds present in vinegar.
What is denatured alcohol?
Write the name and chemical formula of the organic compound which is mixed in small quantities with
ethanol to prepare denatured spirit.
8. Name the organic compound, which can be produced by fermentation of sugar and is a constituent of
beer.
9. Why CNG is considered an environmentally friendly fuel?
10. Name the product other than water formed on burning of ethanol in air.
11. Complete the following reaction
CH3COOH + C2H5OH H2SO4
12. What is the functional group present in propanone?
13. Give the names of the functional groups
(a) ―CHO
(b) >C = O
14. Name the organic acid present in vinegar.
H H H
│ │ │
15. The structural formula of an ester is : H―C―O―C―C―C―H
║ │ │ │
O H H H
Write the formula of the acid and the alcohol from which it is made.
16. What are esters? How are they formed? Where do they occur in nature?
17. What name is given to the reaction which takes place when ethanoic acid reacts with ethanol in the
presence of concentrated sulphuric acid? Name the products obtained in this reaction.
18. What happens when ethanol reacts with (i) sodium (ii) potassium permanganate solution.
19. What is meant by denatured alcohol? What is the need to denature alcohol?
20. (a) Name the organic acid present in vinegar. Write the chemical formula also.
(b) Name the product formed when ethanol burns in air.
21. What are covalent bonds? Write the type of covalent bond present in O2 and N2 molecules.
22. What are esters? Write an equation to show the formation of an ester.
23. An organic compound X in an essential constituent of wine and beer. X is responsible for intoxication
caused by these drinks. Oxidation of X yields an organic acid Y which is present in vinegar. Name the
compound X and Y and write their structured formulae.
24. What happens when ethanoic acid reacts with (i) magnesium, (ii) sodium carbonate, and (iii) sodium
hydroxide? Write the necessary chemical equation in each case.
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25. Give reason for the following:
(a) Why do unsaturated hydrocarbons show addition reactions?
(b) Why is the conversion of ethanol to ethanoic acid an oxidation reaction?
(c) Alcohol supplied for industrial purposes is mixed with copper sulphate.
26. Give chemical equations of the reactions of ethanoic acid with:
(a) Sodium
(b) Sodium carbonate
(b) Ethanol in presence of conc. H2SO4 (d) Sodium hydroxide
27. What is meant by a functional group in an organic compound? Pick out, and name the functional groups
present in the following compounds:
CH3CH2OH, CH3CHO, CH3COCH3, CH3COOH, CH3COOC2H5.
28. Identify the functional groups present in the following compounds and name them according to IUPAC
system: (a) CH3OH, (b) C3H7COOH.
29. The boiling points of three saturated hydrocarbons A, B and C are -162C, -42.2C and -0.5C,
respectively. Which of these three hydrocarbons would have the maximum number of carbon atoms in its
molecule?
30. The melting points of three members A, B and C of a homologous series of hydrocarbons are -183C, 138C, -138C and -130C respectively. Which one of the three would have the lowest number of carbon
atoms in its molecule?
31. Write the molecular formula of the third and the fifth members of the homologous series of carbon
compounds represented by CnH2n-2.
32. Two alkanes A and B have 4 and 6 carbon atoms in their molecules respectively. In which physical state
will they occur at room temperature?
33. Which of the following belong to the same homologous series;
C3H4, C3H6, C4H8, C4H6
34. Out of methane, ethane & propane which one has the highest boiling point?
35. Two alkanes „A‟ and „B‟ have 3 and 5 carbon atoms in their molecules respectively. In which physical
state will they occur at room temperature?
36. Which of the following organic compounds is unsaturated? CH4 or C2H4.
37. Write the names of the isomers represented by the molecular formula C2H6O.
38. Why is a mixture of water and alcohol used instead of water in radiators of vehicles in cold countries?
Give two reasons.
39. Write two tests to demonstrate that acetic acid (CH3COOH) is acidic in nature.
40. Give IUPAC name of CH3COOH.
41. Write the molecular formula of ethanoic acid.
42. Fermentation of sugar solution with enzymes is being carried out in a vessel at 20-30C in the presence
of air. Which organic compound will be produced in this process?
43. Complete the following statement:
Vinegar is prepared by the bacterial oxidation of …………
44. Why have detergents replaced soaps as a washing agent?
45. ………………….is better than soap for washing clothes in hard water.
46. What is meant by functional groups in an organic compound? Give the structural formula of the
functional groups in (a) acetic acid, and (b) ethyl alcohol.
47. An organic compound A has the molecular formula C2H6O. On oxidation in air in the presence of heated
copper as catalyst, it is oxidized to CH3COOH. What is the compound A? Give equation for the reaction.
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48. How do alcohols differ structurally from alkanes? Describe the basic steps involved in the preparation of
ethanol from sugar.
49. An organic compound „X‟ is a constituent of wine and beer. This compound on oxidation forms another
organic compound „Y‟ which is a constituent of vinegar. Identify the compounds „X‟ and „Y‟. Write the
chemical equation of the reaction that takes place to form the compound „Y‟.
50. What is fermentation? How is ethanol prepared by fermentation? Give any two uses of ethanol.
51. An organic compound „X‟ which is sometimes used as antifreeze has the molecular formula C2H6O. „X‟
on oxidation gives a compound „Y‟ which gives effervescence with baking soda solution. What can „X‟
and „Y‟ be? Write their structural formulae.
52. Write the functional group present in the compound CH3NH2 and name it.
53. Write the (i) name and (ii) formula, of the functional group present in the compound, CH3COOH.
54. Name the classes of organic compounds represented by the following formulae;
O
║
(i) C2H5 – NH2
(ii) H3C―C―CH3
55. How are the molecules of aldehydes and ketones structurally different?
56. Write the formulae for the functional groups of alcohols and carboxylic acids.
57. What is meant by „fermentation‟? Write chemical equations for the two steps involved in preparing
ethanol by the fermentation of molasses.
58. Complete the following reaction equation:
CH3CH2OH+Na  ………….
59. Name the main products formed when ethanol is oxidize by an alkaline solution of KMnO4.
60. Write the name and chemical formula of the organic compound which is mixed in small quantities with
ethanol to prepare denatured spirit.
61. Describe the method of producing ethanol by fermentation process. What happens when ethanol (i) is
bunt in air, (ii) reacts with ethanoic acid in the presence of concentrated sulphuric acid & (iii) reacts with
alkaline potassium permanganate? Write balanced equations for each reaction.
62. What is denatured alcohol?
63. Write the name and the chemical formula of the organic acid present in vinegar.
64. Write the formulae for the given compounds and name the functional groups present in each of them:
(i) Ethanoic acid
(ii) Propanone
(iii) Nitromethane
65. Name the organic compounds, which can be produced by the fermentation of sugar and is a constituent of
beer.
66. (a) What is the fermentation process?
(b) What role is placed by yeast in the conversion of canesugar (C12H22O11) to ethanol?
(c) How may the following be obtained from pure ethanol? Express chemical reactions by the
corresponding chemical equations.
(i) Sodium ethoxide (ii) Ethyl ethanoate
(iii) Ethanal
67. What happens when ethanol reacts with (i) Sodium, (ii) chromic anhydride, and (iii) alkaline potassium
permanganate solution? Write the necessary chemical equations for the reactions involved in the above
cases.
68. What happens when ethanoic acid reacts with (i) magnesium, (ii) sodium carbonate, and (iii) sodium
hydroxide? Write the necessary chemical equation in each case.
69. What name is given to the reaction which takes place when ethanoic acid reacts with ethanol in the
presence of concentrated sulphuric acid? Name the products obtained in this reactions.
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70. (a) Write the chemical equation representing the preparation reaction of ethanol from ethanol from
ethene.
(b) Name the product obtained when ethanol is oxidized by either chromic anhydride or alkaline
potassium permanganate.
(c) Give an example of esterification reaction.
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Periodic Classification
Basis of Classification: - Classification is done on the basis of similarities in properties so that the systematic
study could be made about them.
Earlier Attempts at Classification: - In 1803, Dalton published a table of relative atomic weights which
formed important basis of classification at that time.
Dobereiner Law of Triads: - “When the elements are arranged in groups of three in increasing order of
atomic masses, the middle element of a group has the atomic mass and properties roughly the average of the
other two elements.” These elements show similarity in their properties, e.g.,
Atomic mass
Li Na K
7 23 39
Average atomic mass of Ist and IIIrd = 7 + 39 ‗ 23
2
Importance: - The above classification of elements into triads had a great significance in predicting atomic
mass and properties of middle elements. Even in these days, these elements resemble in their properties.
Limitation: - All the elements could not be classified into triads discovered at that time. Only a limited
number of elements could be arranged in such triads.
Newland’s Law Of Octaves: - Newland‟s arranged elements in order of increasing atomic mass. It states
„when elements are arranged in increasing order of atomic mass, the properties of the eighth element are a
kind of repetition of the first just like the notes of music.
Limitations: - All the elements discovered at that time could not be classified into octaves.
Periodicity Of Properties: - The repetition of similar properties after a definite interval is called the
periodicity in properties.
Mendeleev’s Classification: - Mendeleev arranged 63 elements known at that time on the basis of similarities
in properties, i.e., on the basis of similarities in the formulae of their oxides, hydrides, etc., formed by these
elements. He observed that most of the elements were placed in the increasing order of their atomic masses.
It was also observed that there is recurrence of element with similar physical and chemical properties after a
regular interval. That is, every element had properties similar to that of the first.
Groups: - The vertical columns of the periodic table are called „Groups‟.
Periods: - The horizontal rows of the periodic table are called „Periods‟.
Advantages of Mendeleev’s Periodic Table
i. He could classify all the 63 elements discovered at that time on the basis of similarities in properties.
ii. He left gaps for yet to be discovered elements.
iii. He predicted the properties of undiscovered elements and thus helped in the discovery of these elements
later on.
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iv. He named them by prefixing a Sanskrit numeral eka (one), divi (two), tri (three), etc. to the name of the
preceding similar element in the same group, e.g., eka-boron, eka-aluminium, eka-silicon, eka-manganese,
divi-manganese and eka-tantalum.
All
these elements were discovered later and did have properties similar to those predicted by Mendeleev, e.g.,
v. It helped in correction of atomic weights of certain elements on the basis of their position in the Periodic
Table.
Limitations of Mendeleev’s Periodic Table
i. Although most of the elements were placed in the order of increasing atomic masses, increasing order
could not be maintained in all cases, e.g., Cobalt (Atomic mass 58.93) preceded nickel (58.71); tellurium
(127.6) preceded iodine (126.90) but he could maintain similarity in properties, e.g., „Te‟ resembles „Se‟,
„I‟ resembles „Br‟.
ii. Mendeleev‟s Periodic Table did not provide place for noble gases which were discovered later.
iii. There was no place for isotopes in Mendeleev‟s Periodic Table, although they differ in atomic mass.
Modern Periodic Table: - Henry Moseley, an English physicist found that the atomic number (Z) was the
fundamental property of an element and not the atomic mass for classification of elements.
Modern Periodic Law: - “Properties of elements are periodic functions of their atomic numbers, i.e., the
number of protons of electrons present in the neutral atom of an element.”
Elements in a Group
i. They show similar chemical properties due to similar outer electronic configuration, i.e., same number of
valence electrons
ii. They have gradation in properties due to gradually varying attraction of the nucleus and the outer valence
electrons as we go down the group.
Main Features of the Long Form of the Periodic Table
i. It shows arrangement of elements based on modern periodic law.
ii. There are 18 vertical columns known as groups.
iii. There are 7 horizontal rows known as periods.
Elements having similar outer electronic configurations, e.g., having same valence electrons have
been placed in same groups, e.g.
Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
An element „X‟ belongs to 13 group and second period, write formula of its oxide.
Name the chemical who gave “Triad rule” for classification of elements.
State Modern Periodic Law.
What name is given to the horizontal rows in a periodic table?
State “Newlands Law of Octaves” for classification of elements.
The Eka-aluminium predicted by Mendelev was later replaced by which element.
On what basis the position resolved in modern periodic table?
Why was Doberemine‟s system of classification of elements into trials not found to be useful?
Name the element upto which Newlands law of Octave was applicable.
Name the fundamental property used by Mendeleev as the basis of classification.
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11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
Name the Russian scientist to whom the main credit for classifying element goes.
Why inert gases have zero valencies?
Write is given to the vertical columns in periodic table.
What was the prediction of Mendeleev regarding the gaps in his periodic table?
How many elements were known when Mendeleev started his work on classification of elements?
How many groups and periods are there in the Modern periodic table?
What is the name given to group of three similar elements by Dobereiner?
What will be the valency of an element having atomic no. 15?
What is the atomic radius of hydrogen atom?
Give reason why silicon is classified as melalloid.
How does valency vary in going down a group?
Metals are on which side of Modern Periodic table?
X and Y are two elements having similar properties which obey Newlands law of Octave. How many
elements are there in between X and Y?
Name the group of element which was missing in Mendelev‟s periodic table.
How is valency of an element determined?
The present classification of elements is based on which fundamental property of elements.
Name two elements, other than Gallium, whose existence was predicted by Mendeleev.
How does the electronegative character of elements vary along a period of the periodic table?
What would be the valency of an atom containing 8 electrons in its outermost shell?
Among first ten elements in the modern periodic table, name the metals present.
Name the scientist who proposed modern periodic law. On which fundamental property of elements it is
based?
Write the points of differences between Mendeleev‟s periodic table and the Modern periodic table.
State two limitations of Newland‟s law of Octaves.
A, B and C are the elements of a Dobereine‟s triad. If atomic mass of A is & and that of C is 39. What
should be the atomic mass of B?
Name:(i)
The element having two shells completely filled with electron.
(ii)
Any element having one electron in its outermost shell.
From the following group of elements given with their Atomic No.:B (5), Al (13), Na (11), Mg (12), Li (3).
(i) Which of these belong to the same group of periodic table?
(ii) Which of these belong to the same period of periodic table?
In modern periodic table, Cl-35 and Cl-33, having different atomic masses will be kept in different slots
or they would be assigned same position on the basis of their chemical properties. Give reason in
support of your answer.
Determine the valency of your four elements A, B, C and D whose atomic numbers are 12, 13, 16 and 17
respectively.
How does the tendency of an atom to lose electrons vary in a period? Explain why?
What are metalloids? Give two examples.
In group 1 of periodic table, three elements X, Y and Z have atomic radii 133pm, 95pm and 65pm
respectively, giving a reason, arrange them in the increasing order of their atomic number in the group.
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43. Nitrogen (At No. 7) and Phosphorus (At. No. 5) belong to group 15 of the periodic table:b) Write the electronic configuration of the two.
c) Predict whether they are metallic or non-metallic in nature.
44. How does the tendency of an atom to lose electrons vary down the group. Explain why.
45. State three merits of modern periodic table.
46. In what respect is the Mendeleev‟s classification superior to the other classification?
47. What were the three limitations of Mendeleev‟s classification?
48. Atomic radii of the first group elements are given below:
Element (group 1)
Li
k
Na
Cs
Rb
Atomic Radius (pm) 152 231
186
262 244
(i) Arrange them in increasing order of their atomic size
(ii) Name the elements having smallest and largest atoms
(iii) How does the atomic size vary as you go down a group? Why?
49. Atomic radii of the elements of the period are as follows:50. Periods 11 elements:
Be
B
O
N
C
Li
Atomic Radius
: 111
88
66
74
77
152
(i) Arrange them in decreasing order of their atomic radii
(ii) How does the atomic size vary on moving from left to right in a period? Explain why?
(iii) How will the tendency to lose electrons vary on moving from left to right in this period 11?
51. A part of the periodic table is given below:Group period
2.
3.
4.
1
--11
Na
19
K
2
--12
Mg
---
16
8
---
17
9
---
18
--18
Ar
34
Se
---
---
From the table, answer the following questions:(i) Which element is most metallic?
(ii) Which element is most non-metallic?
(iii) Which element is inert gas?
(iv) Which element is smaller in size among O and Se?
(v) Which element is more chemically reactive among Na and Mg?
Write your answer with the reasoning.
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Reproduction
It is the process of producing new individuals of the same species by existing organisms of a species.
Significance of Reproduction
1.Increases the population
2.Helps in evolution
3.Allows perpetuation of species.
Types of Reproduction
Asexual
Sexual
1.
2.
3.
4.
Single parent
Divisions by mitotic
Genetically similar
No Evolution
Involves two parent male and female
Gametes formation by meiosis
Genetically different.
Evolution takes place.
Types of Asexual Reproduction
1. Fission:(a) Binary fission: - Nucleus divides, division of cytoplasm cell finally spits into 2 cell
Ex: Amoeba and Paramoecium
(b) Multiple Fission: - Nucleus divides repeatedly producing many nuclei, each surrounded by small
cytoplasm, within cyst. Cyst breaks up under farourable conditions and off springs are liberated.
Ex: Plasmodium
2. Budding in Hydra: - Bulging appears as a result of repeated mitotic division in the cells, called bud. Bud
slowly enlarges and develops into new body on parent. Finally, it separates and grows as individuals.
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Budding in yeast: - Small protuberance appears on the upper part, grows in size, process continues 3-4
times, resulting chain of yeast cells.
3. Spore Formation: - Sporangium develops from the fungal hypha, nucleus divides with in it, each nucleus
have bil of cytoplasm, spores are liberated and develop into new after reaching substratum.
4. Regeneration: - It is the ability of an organism to replace its last body parts.
The special case of regeneration is Fragmentation one nature breaks into two or more pieces grow into
new individuals. Hydra can regenerate into full nature by only 1/6 mn of its body parts.
Similarly, animals like Hydra, Planaria and sponges also show regeneration.
5. Vegetative Propagation: - A new plant develops from vegetative parts of parent plant.
(i) Natural Vegetative Propagation
Ex: Bryophyllum, Guava Onion, Banana, Garlic
(ii) Artificial Propagation
i) Cutting: – It may be stem, root, leaf etc, it gives off roots when placed partly moist soil.
Ex: Grape, Phalsa and Rose
ii) Layering: – In layering, a flexi-able branch is trimmed of its side branches and leaves and buried in
soil, after sometime underground portion produce new roots.
iii)
Grafting: – The portion of a plant that is grafted on the other plant is called scion and the plant
in which grafting is performed is called the stock, cambium of both stock and scion is fussed.
Ex: Orange, Lemon, Lime
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Advantages of Vegetative Propagation –
1. Cheaper, Rapid method
2. Characters are preserved
3. Useful in seedless plants
4. Require less time.
Disadvantages of Vegetative Propagation –
1. Induces over-crowding
2.No genetic variation
3.Disease of the parent
(a) Stock: - A rooted stem into which a scion or a bud is grafted is called a stock.
(b) Scion: - A piece of young stem or bud which is inserted into a root stock is called scion.
6. Parthenogenesis: - It is the process of development of an organism from an unfertilized egg.
Ex: ants and bees.
7.
Sexual Reproduction
Male and Female gametes fuse to from zygote that develops into a new organism.
Unisexual – Organisms with one sex organ. Ex: Human, Birds
Bisexual – Having both male and female sex organ. Ex: Earthworm, Leech.
(Hermaphrodite)
Fertization – Fusion of male and female gametes.
External
Outside the body
Ex: Fish, Frog
Internal
inside the body
Ex: Birds, Humans
Primary Sex organs – In males test is Produces sperms
(Gonads)
In Females ovary produces egg.
Accessory Sex Organs – In males Penis.
Copulatory Organs – In females Vagina.
Sexual Reproduction in Plants
Non-Reproductive Parts – Sepals (Green)
Petals (Coloured)
Reproductive parts – Stamens
Carpels
(male)
(female)
Pollination – Transfer of Pollens from anther to stigma
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Type of Pollination-Pollination is of two types:
(i) Self Pollination: - Transfer of pollens from stamen to
stigma of the same flower.
(ii) Cross Pollination: - Transfer of pollens from Stamen to
stigma of the flower of another plant of the same species
Cross Pollination
Double-Fertilization in Plants
Synagamy
1 male gamete + Egg
1 male gamete + 2 Polar nuclei
Synagamy + triple fusion
After that ovary
Ovale
Zygote
Double Fertilization
Double Fertilization
Fruit
Seeds
Human Reproductive System
Puberty = Age at which reproductive system becomes functional.
In male – 13 to 14
In Female – 10 to 12
Male – Male gonad (Testis) produces sperm and male hormone (Testostrone) which –
(a) Regulates sperms formations
(b) Maintain accessory sex organ
Female – Female gonad (ovary) produces egg and female hormones (estrogen and progesterone) which
(a) Regulate ovum formation
(b) Maintain sex organs
(c) Secondary sex characters
(d) Development of mammary gland.
Male Reproductive System
(i) Testes  Pair produces sperms and testostrone
(ii) Scrotal Sacs  Provides optimum temperature (1-3°C lower than body) for sperm formation
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Puberty  13 to 14 years
(iii) -Penis  Encloses urethra one pore for urine and sperms.
(iv) Urethra  Delivers sperms.
(v) Vas Deferens  Transport sperms from testes to urethra Human female Reproductive system
Female Reproductive System
(i) Ovary  Located near the kidney, perform dual function (i) Produce ovum
(ii) Female sex hormones.
(ii) Fallopian tubes  Transport ova from the ovaries and site of fertilization.
(iii)Uternus It is a muscular structure where Implantation takes places.
(iv) Vagina  Tubular structure, also called as „Birth Canal‟ having two separate opening.
Sexual Cycle in Female
1. The ovaries start producing ovum at a definite age called puberty.
2. After this age, ovaries exhibit cycle of events at definite intervals.
3. Ovarian follicles grow into follicles a done follicle develops into ovum, when this ovum released then it
is called ovulation.
4. Simultaneously, the inner living of uterus becomes thick and spongy to get prepared for receiving the
developing zygate in case fertilization occurs.
5. If the ovum does not get fertilized then the thick and soft inner living of uterus is not longer needed and
hence it breaks down in the form of bleeding know as Menstrual flow (Menstruation).
6. The cycle of events taking place in the ovaries and uterus every 28 days and called Menstrual Cycle.
Notes:  Ovulation takes place in the oxide of the menstrual cycle (14th day)
 The commencement of menstruation at puberty is termed of menarche.
 The stoppage of menstrual flow and other events is formed menopause.
Fertilization: - Fertilization is possible if copulation has taken place during the middle of the menstrual
cycle because ovulation takes place on the 14th day and reaches the fallopian tube on the same day.
1. The sperm is introduced inside the female genital tract by the process called copulation.
2. Out of millions of sperms, one sperm fertilizes the ovum it is known as fertilization and zygate is
formed.
3. The development of embryo starts immediately.
4. Embryo moves down and gets attached to it‟s thickened in near wall, which is called as implantation.
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5. After implantation, a special tissue develops between uterine wall and the embryo called Placenta.
6. Form Placenta, foctus gets all developmental needs.
7. The development of foctus inside the uterus till birth is called gestation.
8. Parturition is birth of the fully developed foctus.
9. The average duration of human pregnancy is about 280 days.
10. Pregnancy is calculated from the first day of the last menstrual cycle.
Sexually Transmitted Diseases (STDs)
1. Syphilis
2. Trichomoniasis
3. Gonorrhea
Symptom: - Burning sensation at urivation AIDS causative agent HIV.
Questions
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How does plasmodium undergo fission?
Which cells are responsible for budding in Hydra?
Name the structure into which following develops: - the plumule and redicle.
Name any one biological process not necessary to stay alive.
How spirogyra reproduces by fragmentation?
Where are the testes located in human beings?
Why simply copying of DNA in a dividing cells not enough to maintain continuity?
On which plant can you find buds on its leaves?
Write the scientific name of the bread mould.
Write the ill effects of misuse of surgery.
For what specific reason have the testes, specific location.
Where does the zygote get implanted?
Correlate the rate of general body growth and maturation of reproductive tissue during puberty.
Which two important chemical substances are delivered to develop embryo through Placenta?
How change in hormonal balance prevents pregnancy?
Write one side effect of loop placed in uterus?
Which structures need to be blocked in males and females respectively to prevent pregnancy?
Name the tissue in mother‟s body that provides nutrition to developing embryo.
Name the chemical methods of preventing pregnancy.
Expand AIDS.
Which of the two has faster rate:- Asexual or Sexual reproduction.
Name some of the devices used as mechanical method for preventing pregnancy.
During Spore formation in Rhizopus, which cells undergo reductional division?
Name the female reproductive part in centre of flower.
In which structures of flower are ovules present?
Normally how many copies of DNA are formed in a reproducing cell?
Identify the place in flower where zygote repeatedly divide forming embryo.
From which part of the flower do following develop:- the fruit and the seed.
Name the cell organelle in which most of the amount of DNA is concentrated.
Why is children sex ratio alarmingly declining in our country?
Write the names of area where buds are found in leaves of Bryophyllum.
Name the two groups of living organisms which have lost capacity to produce seeds.
Enlist any four plants which have lost capacity to produce seeds.
Why is greater degree of accuracy of DNA copying mechanism vital for survival?
Write two important functions of testosterone.
Distinguish between fission taking place in Amoeba and Leishmania.
Distinguish between asexual and sexual mode of reproduction.
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38.
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Write two advantages of plants raised by vegetative propagation over those raised from seeds.
Trace the path that a sperm cell undertakes before copulation.
Compare unisexual flower with bisexual flower.
Enlist role of secretion of seminal vesicle and prostate gland.
Name two bacterial and two viral STD.
A newly born girl child. In her ovaries carries several immature eggs. Enlist the reason for the delay of
process of biological maturation of these eggs.
Compare self-pollination with cross- pollination.
Describe the changes in lining of uterus in case in egg is not fertilized.
Write most common mode of reproduction in the following Rhizopus, Hydra Paramecium and yeast.
Through not necessary to stay alive yet reproduction is vital. Give reason.
Write the disadvantage of vegetative propagation.
Name any two unisexual and any two bisexual flowers.
Sketch the diagram of Rhizopus showing spores.
Draw a diagram only to show multiple fission in plasmodium.
Enlist the body changes taking place during the early adolescence in boys and girls respectively.
The consistency of DNA copying facilities stability of population of any species. Elaborate.
Elaborate upon regeneration with the help of a diagram by citing suitable example.
Describe the reproduction through Spore formation in Rhizopus.
Draw a longitudinal section of a bisexual flower.
Differentiate between the germ cells of simple organism and more complex organisms.
Describe the role of variation for survival of species over period of times.
Define the following terms: - Fragmentation, Binary fission, Asexual reproduction, Fertilization, and
Sexual reproduction.
Describe the process of zygote formation in angiosperms with the help of a well- labelled diagram.
Explain the female reproductive systems in human beings with the help of a well- labelled diagram.
Explain the male reproductive structure in human beings with the help a well- labelled diagram.
Define reproduction explain its various types.
Differentiate between sexual reproduction and asexual reproduction?
Explain fission with the help of example
Explain the spore formation process.
Define budding and fragmentation?
Explain the various types of vegetable propagation.
Define Parthenogenesis?
Define scion and stock.
What do you mean by unisexual and bisexual organism?
What do you mean by fertilization? Explain its types also.
Define copulation and necessary sex organ?
Draw and explain reproductive parts of plants?
The harmones play very important role in the process of reproduction. Explain the statement.
What do you mean by “Gronad”.
Explain the female reproductive system with the help of diagram.
Explain the male reproductive system with the help of diagram.
Write a short note on sexual cycle in female.
Describe the major events after ferti9lization on female?
Explain the various methods of populati8on control?
Define Implantation, placenta, gestation, vasectomy, tubectomy, zygote, Emboyosac, Microphyle.
Define OCs and IUcDs.
Differentiate between
(a) Sexual and Asexual
(d) Tubectomy and vasectomy
(b) Self Pollination and Cross pollination (e) Male reproductive system & female reproductive system.
(c) Menarche and Menopause
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Heredity and Evolution
HEREDITY: - Transmission of character from parents to the off springs: ie from one generation to
the next is called heredity.
VARIATION: - The differences shown by the individuals of a species and also by the off springs of
the some parents are referred to as variation.
Importance of variations
I. They enable the organisms to adapt themselves in changing environment.
II. Variations from the bases of heredity.
III. They form raw materials from evolution and development of new species.
IV. Variation are useful to species not to an individual for an example:a. If one bacterium divides, the resultant two bacteria divide as again, the four individual
bacteria generated would be similar with minor difference due to small inaccuracies in
DNA copying.
b. Depending on the nature of variations, Different individuals would have different
advantages like bacteria, which can withstand heat will survive heat wave better.
c. Selection of variants by environment factors from the bases of evolutionary processes.
HEREDITY AND VARIATION IN ASEXUAL REPRODUCTION: In asexual reproduction, organisms raised are the exact copies of their parents.
 They tend to preserve the similarities among all the individuals belonging to a given line of
descent.
 They exhibit very little variations due to some environmental factors or mutations which are
sudden changes in genes. Out of these two factors, only mutations are heritable.
HEREDITY AND VARIATION IN SEXUAL REPRODUCTION: In sexual reproduction, two parents are involved and there is formation and fusion of gametes.
 The off springs show variations from their parents due to crossing over and exchange of gene
segments.
 They are not carbon copies of their parents, due to recombination of parental genes. So,
variations which occur are heritable.
INHERITED TRAITS: - It is the transmission of particular characteristics from parents to their off
springs, generation to generation. Which bear all basic features with great deal of variation?
GREGOR JOHANN MENDEL: - Was an Austrian Geneticist and regarded as the „Father of
Genetics. His experiments with garden peas and the inferences together with his interpretations
constitute the foundation of modern genetics.
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Mendel selected garden pea because
I. If had a short life cycle.
II. Garden pea plant had distinet, easily detectable contrasting variants of features.
III. In their bisexual plants, artificial cross fertilization could easily be achieved.
MENDEL’S EXPERIMENTAL TECHNIQUE: b) Selection of pure parent plants
c) Production of first generation of plants by cross breeding.
d) Raising of second and subsequent generations by self-fertilization of hybrids.
MENDEL’S MONOHYBRID CROSS: - A breeding experiment dealing with a single character is called a
monohybrid cross.
Parental
round Seeds
Male pea plant with
Female pea plant with Generation
wrinkled Seeds
X
(Cross pollination)
All plants with round
Seeds
(Self pollination)
F1 Generation
F2 Generation
Round Seeds
Wrinkled Seeds
MENDEL’S CONCLUSIONS FOR MONOHYBRID CROSS: - Only one of two contrasting characters
appeared in F1 generation However in F2 generation, both the parental trait appeared in certain proportion.
MENDEL’S DIHYBRID CROSS: - A breeding experiment dealing with two characters at the same time is
called a Dihybrid Cross
Parental
Generation
Male pea plant with round
and yellow Coloured Seeds
Female pea plant with wrinkled
and green coloured Seeds
X
(Cross pollination)
All plants with round
and yellow coloured
Seeds
F1 Generation
(Self pollination)
F2 Generation
___________________________________________________________________________
Plant with round and
Yellow coloured Seeds (315)
Parental combination
Plant with round and
Green coloured Seeds (108)
new combination
Plant with wrinkled and
Yellow coloured Seed(101)
Parental combination
Plant with wrinkled
and green coloured Seeds (32)
MENDAL’S CONCLUSIONS FOR DIHYBRID CROSS: - When two contrasting pairs of traits
were considered simultaneously, only one parental combination appeared in F1 generation. However,
in F2 generation, raired by self-pollination, four combinations of traits appeared. These included two
parental type traits and two new combinations in approximately same proportion.
MENDEL’S RESULT: - There is pair of unit factors controlling each character in pea plants, one
inherited from each parent. At the time of reproduction. Which gametes are formed, these factors
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segregate so that each gamete receives only one factor of each character. This is called LOW OF
SEGREGATION.
 In F1 generation, only one character was expressed. Mendel called it as dominant character. The
character which was not expressed was termed recessive character „This Phenomenon of
appearance of only one of two contrasting traits F1 generation, is termed as dominance.
 The character is not lost even when they are not expressed.
 From the F2 generation of a dihybrid Cross, Mendel postulated that inheritance of factors
controlling of the other. „This is called law of independent assortment.
CONTROL OF TRAITS:a) A section of DNA that provides information for one protein in cell is called gene.
b) If the proteins work efficiently, the traits get expressed in a better-way.
c) For example, plants height depends on the amount of growth hormone released by protein. If the protein
is efficient, more growth hormone will released and the plant will be taller. But if the protein is
inefficient, the plant will be shorter, Thus genes controls the traits.
STABILITY OF THE DNA OF THE SPECIES:a) During sexual reproduction, both the parents contribute equally to the DNA of the progeny by
contributing one set of genes through germ cells.
b) In the cells, two sets of genes are not parents as separate single threads of DNA. Instead these exist as
separate independent pieces, called Chromosomes. Each cell has two copies of each chromosome, one
each from male and female parents.
c) When the germ cells are formed, every germ cell-receives one chromosome from each pair and these
may be either of maternal or paternal origin. When these male and female germ cells combine during
fert6ilization, normal number of chromosomes in the progeny is restored ensuring the stability of the
DNA of the species.
SEX OF A CHILD DEPENDS ON WHAT HAPPENS AT FERTILISATION:a) If a sperm carrying x chromosome fertilization ovum which carries x chromosome, then the child born
will be a girl.
b) If a sperm carrying y chromosome fertilization ovum which carries x chromosome, then the child born
will be a boy.
c) Thus, the sperm determines the sex of the child.
ORIGIN OF LIFE: - Stanley L. Miller and Harold C. Very in 1953 designed a glass apparatus and
simulated the conditions that thought to have existed on Primitive earth. They circulated a mixture of (CH4)
(NH3) (H2) and (H2O) in this apparatus. These gases were believed to prevail in the primitive earth. The
mixture was maintained at a temperature just below 100C. THEY PROVIDED ENERGY FOR
INTERACTION OF GASES IN THE FORM OF ELECTRIC SPARKS IN THE GAS FLASK. At the
end of week they had been converted to simple organic compounds such as amino acids, simple sugars.
EVOLUTION: - is the sequence of gradual changes which take place in the primitive organism over millions
of years and new species are produces. Since the evolution is of the living organisms, so it is called
‘ORGANIC EVOLUTION’.
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VARIATION IN POPULATIO: AN EXAMPLE: - 12 red beetles live in a green leafy bush grows by sexual
reproduction and generate variation.
SITUATION-I
a) Crows eat these beetles, leaving only fewer beetles available for reproduction.
b) Due to colour variation during reproduction, only pone green beetle evolves and therefore, all its
progeny beetles become green.
c) Crows cannot eat them, resulting more green beetles than red ones in the beetle population.
d) This type of variation gives a survival advantage.
 “Natural selection is the phenomenon where in nature, in the wild, selects traits favorable to the species
in its environment.”
SITUATION-II
a) Due to colour variation during reproduction, a blue colour beetle appears and all its progeny beetles
become blue.
b) Crows can see both red and blue beetles and therefore eat them.
c) Initially there are less number of blue beetles and more of red beetles.
d) Then an elephant stumps on the bushes and bills most of the beetles By chance, few beetles that
survived were mostly blue.
e) Thus, the blue beetle population slowly expands.
f) There is no survival advantage on this variation and provides diversity without adaptation.
 “The elimination of the genes of certain traits from the small population when section of the species
population dies of natural or migrates to other region is called genetic drift. It alters the gene frequency of
the remaining population.”
SITUATION-III
a) As the beetle population begins to expand, the bushes suffer from a disease and amount of leaf available
b)
c)
d)
i.
for beetle have reduced.
Thus, the beetles are poorly nourished and the average weight of an adult beetle has decreased.
After few years, the plant disease is eliminated and enough food is available for the beetles. Thus the
beetles have come back to its normal size and weight.
This change is not inherited over generation.
While considering the third situation, we find that there are two kinds of traits in every organism.
i. Inherited Traits
ii.
Acquired Traits
INHERITED TRAITS: - These traits are controlled by specific genes and are passed on passed on from
one generation to another. Any alteration in the DNA will be passed on. Through germ cells, to the
progeny resulting in variations in them.
ii. ACQUIRED TRAITS: - Certain traits are acquired by organisms in their life time. For instance,
decrease in the body weight of beetle due to starvation is an acquired trait by the beetle during their life
time it involves changes in the non-reproductive tissue caused by environmental factors. It will not bring
any change in the DNA. Therefore ever if some of the generations of beetle are low in weight because of
starvation, this trait cannot be inherited by the progeny over generation.
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SPECIATION: - Origin of new species from the existing one is called speciation.
 Reproductive isolation refers the mechanisms which check the population of two different groups from
interbreeding.
 CHARACTERISTICS: - It is the detailed appearance or behaviour of a particular form or a particular
function. For example the four limbs of human beings are characteristics and that plants can perform
photosynthesis is also a characteristic.

CLASSIFICATION: - It is the arrangement of organisms into a series of groups based on physiological,
biochemical, anatomical or other relationships.
 EVOLUTIONARY RELATIONSHIP WITH CLASSIFICATION : The more common characteristics two species have, the more closely they are related.
 The closer the species are, the more nearer they have a common ancestor.
 For example, a brother and a sister are closely related and they have a common ancestor, their
parents in the first generation.
 A girl and her first cousin are closely related but less related than her brother. The cousins have a
common ancestor, their grandparents in the second generation. Thus, evolutionary relationships are
traced in the classification of organisms.
 HOMOLOGOUS ORGANS: - Are there organs which have the same basic structural design and
development origin but have different function and appearance.
 Ex: The forelimb of a frog, a lizard, a bird and a man seem to be built from the same basic design
of bones but they perform different functions.
 ANALOGOUS ORGANS: - Are those organs which have different basic structural design and
developmental origin but have similar appearance and perform similar functions.
 FOSSILS: - They are all the preserved traces or remains of living organisms of geological past.
 When organism due, their dead bodies decompose and get lost.
 But some parts of the body may be in the environment that does not ret in decomposed.
 FOSSIL DATING:- The age of fossils can be estimated by two ways:
 If we dig into the earth and start finding fossils, it can be assumed that the fossils closer to the
surface are more recent to the fossils closer to the surface are more recent to those found in deeper
layers.
 By detecting the rations of different isotopes of the same element in the fossil material.
 EVOLUTION BY STAGES:  Complex organs may have evolved because of the survival advantage of the intermediate stages.
 Complex organs like eyes are created bid by bid over generation which is a very popular
adaptation. The structure of eye in all organisms is different enough to have separate evolutionary
origins.
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 Organs or features may be adapted to new functions during the course of evolution. As for
example, feathers are thought to have evolved for warmth and later adapted for flight.
 Some dissimilar looking structures also evolved form common ancestor.
Ex: - Wild cabbage plants from which different vegetables are generated by artificial selection like
broccoli, cabbage, cauliflower etc.
 EVOLUATION VERSUS PROGRESS: - Evolution cannot be said to progress from lower forms to higher
forms. It seems to have given rise to more complex body designs even while the simpler body designs
continue to flourish. For Exp: Human beings have not evolved from chimpanzees, but both have a common
ancestor.
 In tracing the family tree of species, we must remember that: There exists the possibility of multiple branching at each and every stage of this process.
 Species does not necessarily get eliminated to give rise to a new one ex, of beetles. This of course,
will depend on the prevailing environment.
 The newly formed species is not, in any way, better than the older one. It is in fact the natural
selection and genetic drift which have together led to the formation of a population that cannot
reproduce with original one.
Human Evolution: - The study of human evolution indicates that all of us belong to a single species that
evolved in Africa. The earliest member of the human species. Homosapiens can be traced there.
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Questions
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37.
What is the chemical nature of enzymes?
Which of the two exhibit greater variation: Asexual or sexual reproduction.
What is heredity?
Define gene.
At which place on earth did humans appeared first?
Why all the variants don‟t have equal chances of surviving?
Give the name of plant studied by Mendel.
Which one of the two is shorted in length „X‟ or „Y‟?
Determine the sex of progeny inheriting X chromosome from its father.
Name any one place in India where Dinosaur‟s skull fossil was found.
Name the acid which is an information source for making proteins in cells.
Name any one invertebrate fossil.
Dead remains of two organisms A and B were buried. Later only B‟s fossils were found. But not A‟s.
Give reason.
Give the term of the following: It is simply generation of diversity and shaping of diversity by
environmental selection.
Green and red coloured seeds are recessive and dominant trait respectively. Out of F1 and F2 in which
generation will the green seed appear.
Species A share ten characteristics with B. Species C share fifteen characteristics with D. Which of the
two pairs share closer relation?
Write the ten possible range of pH of DNA.
Give an example of artificial selection from plants.
Name any one fish fossil.
Identify the group of organism that can be found in places like hot springs deep sea, thermal vents and
ice in Antarctica.
Define a chromosome. What are the total numbers of chromosomes in sperm cells of human males.
XY and XX are sex chromosomes. Write the contribution of father and mother in each of these sets?
Define acquired traits. Give examples.
Name any four methods used for studying human evolution.
Distinguish between dominant and recessive traits.
Describe the two ways of determining the age of fossils.
Distinguish the wing of a bird from wing of a bat.
Evolution should not be equated with progress. Give reasons.
What is genetics? Who is known as the father of genetics?
The reproductive cell undergoes reductional division. Write the number of different types of gametes
produced from one XX and one XY. Also find the ratio of X to Y.
“A tratil might be inherited but not expressed.” Elaborate citing an example from Mendel‟s experiments.
Explain possible ways of evolution of an eye.
In Mendel‟s experiment F1 progeny had no halfway of intermediate features. Explain the statement by
giving a suitable example.
Describe how the number of chromosomes is conserved in progenics.
Explain how genes control traits.
Enlist any three contrasting visible characteristics studied by Mendel in pea plant.
Explain Speciation.
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SARASWATI STUDY POINT
38. Tallness and wrinkled seeds are dominant traits against shortness and round seed. Which feature (s) will
be expressed in F1 and F2 respectively. Also write the different pairs of the traits possible in this case in
F2.
39. Trace the path of Y chromosomes received by a progeny since formation in the parent.
40. What is the evolutionary relationship between human beings and chimpanzee?
41. Differentiate between homologous and andlogous organs. Give examples. Briefly describe possible
evolution of feathers.
42. Write short notes on the following evolution and fossils.
43. Design an experiment to show that traits are independently inherited.
44. Define the following terms: - Gene flow, hierarchy characteristic recessive traits and genetic drift.
45. With the help of a diagram explain the mode of sex determination in human beings. Write any two
inherited traits in human beings.
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Reflection and Refraction
1.
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30.
If the size of the image obtained by spherical mirror is twice the size of the object. Identify the kind of
mirror.
Naseem obtained a magnification of 1 with concave mirror of focal length 10 cm. What is the object
distance from mirror?
Suggest a spherical mirror from which the image obtained is always virtual and small.
If an incident ray passes through centre of curvature of concave mirror, from where will it pass after
reflection?
If the angle between plane mirror and incident ray is 30º, what will be the angle of reflection?
How does speed of light change when it travels from optically rarer to denser medium?
Why does a ray change its path when it passes from one medium to another medium?
Name the type of spherical lens where image formed is always small & erect.
The medium of curvature of a concave mirror is 3 cm. Find its focal length.
Define refractive index of medium.
Define Diopter.
Define magnification.
Name a mirror having focal length-15 cm.
Due to which property of light, sharp shadows of opaque objects are obtained?
What is the power of lens having focal length 2cm?
In which case speed of light is more? When:- (i) µ = 1.5 (ii) µ = 2.4
What kind of mirror is used for head lights of cars?
Two medium with refraction index 1.31 & 1.50 are given in which case?
The paper got burnt when a concave mirror was kept 15.3cm away from it. Find the focal length &
radius of curvature of mirror?
A concave mirror produces 4 times magnified real image of an object placed at 10cm in front of it. Find
the position of the image?
Draw a path of light as it enters from:(i)
Air to gas
(ii)
Glass to air.
The lens has power of +2.5D. Find the focal length and nature of the lens.
Which spherical mirror is used as shaving mirror & why?
State laws of refraction.
Draw the ray diagram of image formed when object is placed between pole and the focus of a concave
mirror.
Draw the ray diagram of image formed when an object is placed in front of convex lens at:(i)
Centre of curvature.
(ii)
Between focus and optical centre.
State nature, size and position of the image.
Draw a ray diagram for image formation, when the object is placed at F in front of concave lens.
A concave lens has a focal length of 15cm. At what distance should the object from the lens be placed,
so that it forms an image at 10cm from the lens? Also, find the magnification of the lens?
In case of glass-slab, emergent ray is parallel to incident ray, explain.
If an object of 4cm height is placed at a distance of 15cm away from the convex lens of focal length
10cm. find the nature, size, position of the object. Find its magnification.
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31. Comment on the size, position of the image formed by a concave mirror of focal length 15cm, when an
object is placed at:(i) 20cm
(ii) 10cm
(iii) 35cm
in front of a mirror without calculation.
32. A concave mirror of focal length 15cm is used to obtain an enlarged image of 6cm height. The screen is
placed at a distance of 37.5cm from the mirror. Find the position of the object from the mirror, height of
an object, nature of the image formed.
33. An object is placed 12cm away from the optical centre of a lens. Its image is formed exactly midway
between the optical centre and the object.
(i)
What is the nature of the lens?
(ii)
Is the image formed erect or inverted?
(iii)
Draw ray diagram to show the image formation.
34. Define focal length and radius of curvature for a spherical mirror.
35. What is the relationship between the focal length and radius of curvature in the case of a concave mirror?
36. If the radius of curvature of a concave mirror is 36 cm, what is its focal length?
37. Define the focus and the focal length of a convex mirror.
38. For a plane mirror magnification M = +1. What does this signify for (a) M = 1, and (b) positive sign of M?
39. Explain with a suitable diagram how does a concave mirror converge a parallel beam of light rays?
40. Define and show on a neat diagram the following terms for a concave mirror.
(i) pole
(ii) aperture (iii) radius of curvature
(iv) principal axis
(v) principal focus
41. For which position of an object, a concave mirror forms a real image equal in size to the objects?
42. For which position of the object does a concave mirror produce an inverted, magnified, real image?
43. For what position of an object, a concave mirror forms an enlarged virtual image?
44. One wants to see an enlarged image of an object in a mirror. What kind of mirror should one use & where
should the object be placed?
45. Name the spherical mirror which can produce a real and diminished image of the object.
46. Where should an object be placed in front of a concave mirror so as to obtain its magnified erect image?
47. Describe the nature of an image formed when an object is placed at a distance of 20 cm from a concave
mirror of focal length 10 cm.
48. If an object is placed at a distance of 8 cm from a concave mirror of focal length 10 cm, discuss the nature
of the image formed by drawing the ray diagram.
49. What is the position of the image when an object is placed at a distance of 30 cm from a concave mirror of
focal length 20 cm?
41. Find the size, nature, and position of the image formed when an object of 1 cm size is placed at a distance
of 15 cm from a concave mirror of focal length 10 cm.
42. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Then, the
position of the object should be
(i) Between the focus and the centre of curvature (iii) Beyond the centre of curvature
(ii) At the centre of curvature
(iv) Between the pole of the mirror and its
focus.
43. No matter how far you stand from a spherical mirror, your image appears erect. The mirror may be
(i) Plane
(ii) Concave
(iii) Convex
(iv) Either plane or convex
44. Complete the path of ray of light after reflection at the mirror as shown in the given diagram.
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s
45. Find the focal length of a convex mirror whose radius of curvature is 32 cm.
46. The radius of curvature of a convex mirror used on a moving automobile is 2.0 m. A truck is coming
behind it at a constant distance of 3.5 m. Calculate (i) the position, and (ii) the size of image relative to
the size of the truck. What will be the nature of the image?
47. An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position
and nature of the image.
48. A concave mirror produces three times magnified real image of an object placed at 10 cm in front of it.
Where is the image located?
49. An object of size 7.0 cm is place at 27 cm in front of a concave mirror of focal length 18 cm. At what
distance from the mirror should a screen be placed, so that a sharp focused image can be obtained? Find
the size and the nature of the image.
50. Show that the mirror formula for spherical mirror holds good for a plane mirror too.
51. An object is 5.0 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of
curvature 30 cm. Find the position of the image, its nature and size.
52. Which mirror has a wider field of view?
53. What kind of mirror is used in vehicles to see the traffic following it?
54. If you want to see an enlarged image of your face, state whether you will use a concave or a convex
mirror.
55. A man standing in front of a special mirror finds his image having a very small head, a fat body and legs
of normal size. What are the shapes of the three parts of the mirror?
56. Draw ray diagrams to show the formation of images when the object is placed in front of a concave
mirror.
(i) between its ole and focus points,
(ii) between its centre of curvature and focus point.
57. What focal length can be assigned to a plane mirror?
58. Find the position, nature and size of the image of an object 4 cm high placed at a distance 10 cm from a
concave mirror of focal length 20 cm.
59. What are the value of (i) the angle of incidence, and (ii) the angle of reflection for normal incidence on a
place mirror surface?
60. Where will the image be formed by a concave mirror when an object is placed between the pole and the
focus point of the mirror?
61. See figure alongside and with the help of congruent
triangles, show that A‟C = AC and A‟B‟ = AB.
Interpret the results.
62. A ray of light travels from the air into glass. For an angle of incidence of 37, the angle of refraction is
24. What is the refractive index of the glass?
63. A ray of light travelling from air enters a liquid at an angle of 45 with the normal. If the corresponding
angle of refraction is 30 find out the refractive index of the liquid with respect to air.
64. From the diagram given alongside, calculate
(i) the angle of incidence (ii) the angle of refraction
(iii) the refractive index of the substance X
65. Light enters from air to glass place having refractive index 1.50. What is the speed of light is the glass?
The speed of light in vacuum is 3 x 108 m/s.
66. The refractive index of dense flint glass is 1.65, and for alcohol, it is 1.36 with respect to air. What is the
refractive index of the dense flint glass with respect to alcohol?
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67. Light of wavelength of 500 nm in air enters a glass plate of refractive index 1.5. Find (i) speed, (ii)
frequency, and (iii) wavelength of light in glass. Assume that the frequency of light remains the same in
both media.
68. Which of the following lenses would you prefer to use while reading the small letters found in a
dictionary?
(a) A convex lens of focal length 50 cm
(b) A concave lens of focal length 50 cm
(c) A convex lens of focal length 5 cm
(d) A concave lens of focal length 5 cm
69. What is a lens? How many types of lenses are there?
70. Why is a convex lens called a converging lens? Explain with the help of a diagram.
71. What is a lens? Distinguish between a convex and a concave lens.
72. Explain with the help of a diagram, why is a concave lens called divergent lens?
73. If the image formed by a lens is always diminished and erect then what is the nature of the lens?
74. If the image formed by a convex lens is of the same size as that of the object, then what is the position of
the image with respect to the lens?
75. Find the positions, size and nature of the image of an object 5 cm high which is placed 10 cm in front of a
convex lens of focal length 6 cm.
76. A diverging or concave lens of f = 15 cm forms an image 10 cm from the lens. Draw a scale diagram, and
prove that the object is placed 30 cm away from the lens.
77. An object 4 cm high is placed at a distance of 27 cm in front of a convex lens of focal length 18 cm. Find
the position, nature and size of the image formed.
78. An object 5 cm high is kept 25 cm away from a converging lens (convex lens) of f = 10 cm. Draw a
suitable diagram and find the position and size of the image formed. Is the image real or virtual?
79. Where should an object be placed so that a real and inverted image of the same size is obtained by a
convex lens?
(i) at the principal focus of the lens
(ii) at twice the focal length
(iii) at infinite
(iv) between the optical centre of the lens and its focus.
80. A spherical mirror and a thin spherical lens have a focal length of -15 cm each.
(i) both are concave
(ii) the mirror is concave, but the lens is convex
(iii) both are convex
(iv) the mirror is convex, but the lens is concave.
81. A convex lens forms a real and inverted image of a needle at a distance of 50 cm from the lens. Where is
the needle placed in front of the convex lens, so that this image is of the same size as the object? Also,
find the power of the lens.
82. An object of height 5 cm is kept 25 cm away from a converging lens of focal length 10 cm. Draw the ray
diagram and find the position, size and nature of the image formed.
83. An object is placed at a distance of 50 cm from a concave lens of focal length 20 cm. Find the nature and
position of the image.
84. An object placed 50 cm from a lens produces a virtual image at a distance of 10 cm in front of the lens.
Draw a diagram to show the formation of image & calculate the focal length of the lens.
85. A diverging or concave lens of f = 15 cm forms an image 10 cm from the lens. How far is the object
placed from the lens? Draw the ray diagram.
86. Find the power of a concave lens of focal length 2 m.
87. Find the focal length of a lens of power – 2.0 D. What type of lens is this?
88. The power of a lens is 2.5 dioptre. What is the focal length and the type of lens?
89. A person having a myopic eye uses a concave les of focal length 50 cm. What is the power of the lens?
90. A convex lens & a concave lens of focal length 50 cm and 40 cm respectively are combined together.
What is the power of the combination?
91. Two thin lenses of power, + 3.5 D and – 2.5 D are placed in contact. Find the power and focal length of
the combination.
92. A doctor has prescribed a corrective lens of power + 1.5 D. Find the focal length of the lens. Is the
prescribed lens diverging or converging?
93. In which unit is the power of a lens measured?
94. What is the SI unit of the power of a lens?
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95. A convex lens has a focal length of 10 cm. What is its power?
96. A person having a myopic eye uses a concave lens of focal length 50 cm. What is the power of the lens?
97. (a) State snell‟s law of refraction of light.
(b) A transparent medium a floats on another transparent medium B. When a ray of light travels obliquely
from a into B, the refracted ray bends away from the normal. Which of the media A and B is optically
denser and why?
98. With the help of ray diagrams show the phenomenon of total internal reflection of light and the concept of
critical angle for a transparent medium.
99. (i) What is meant by „critical angle‟ for a ray of light going from one medium into another?
(ii) What is the consequence of making angle of incidence of light at an interface, greater than the critical
angle?
(iii) Why does a cut diamond shine more than a glass piece with diamond cut?
100. (i) Draw a ray diagram to show passage of two rays of light through a rectangular slab of glass, when the
angle of incidence is zero in one case and a little less than 90 in the other case.
(ii) Prove that if a ray enters a rectangular glass slab obliquely & emerges from the opposite face, the
emergent ray will be parallel to the incident ray.
101. A convex lens has a focal length of 25 cm. Calculate the distance of the object form the lens if the image
is to be formed on the opposite side of the lens at a distance of 75 cm from the lens. What will be the
nature of the image?
102. What is the power of a concave lens of focal length 25 cm?
103. What will be the focal length of a lens whose power is given as + 2.0 D?
104. Find the position, nature & size of the image formed by a conves lens of focal length 12 cm of an object
3 cm high placed at a distance 20 cm from it.
105. A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 12 cm of
an object 3 cm high placed at a distance 20 cm from it.
106. Name the three primary colours of light. A flower has magenta colour in white light. What will its colour
appear to be when viewed separately under each of the lights of primary colours? What are
complementary colours of light?
107. Light enters from air into a glass plate which has a refractive index of 1.50. Calculate the speed of light
in glass. The speed of light in air is 3.0 x 108 m s-1.
108. With respect to air the refractive indices of water and benzene are 1.33 and 1.50 respectively. Calculate
the refractive index of benzene with respect to water.
109. The image obtained with a convex lens is erect and its length is 4times the length of the object. If the
focal length of the lens is 20 cm, calculate the object and image distances.
110. A needle placed 45 cm from a lens forms an image on the screen placed 90 cm on the other side of the
lens. Identify the type of the lens and determine its focal length. What is the size of the image if the size
of needle is 5.0 cm?
111. Calculate the distance at which an object should be placed in front of a convex lens of focal length 10 cm
to obtain an image of double its size.
112. The image of a needle placed 10 cm from a lens is formed on a wall 20cm on th other side of the lens.
Find focal length of the lens & size of image formed, if the size of object needle is 2.5 cm.
113. An object is placed at a distance of 50 cm from a concave lens of focal length 30 cm. Find the nature and
position of the image.
114. An object of height 2 cm is placed at a distance of 15 cm from a concave lens of power – 10 dioptre.
Find the size of the image.
115. A thin lens has a focal length of – 25cm. What is the power of the lens? Is it convex or concave?
116. A convergent lens of power 8 D is combined with a divergent lens of power – 10 D. Calculate focal
length of the combination.
117. A concave lens is kept in contact with a convex lens of focal length 20 cm. The combination works as a
converging lens of focal length 100 cm. Calculate power of concave lens.
118. Find the focal length and nature of lens which should be placed in contact with a lens of focal length 10
cm so that the power of the combination becomes 5 dioptre.
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Human Eye
Important Terms and Concepts:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.

Eye: - The natural optical device using which man could see objects around him. It forms an inverted,
real image on a light sensitive surface called the retina.
Retina: - The light sensitive surface of eye in which image is formed. It contains rods and cones. Rods
respond to light cones respond to the colour. The cells generate signals which are transmitted to the
brain through optical nerves.
Cornea and Aqueous Humour: - Acting as lens, they provide the refraction for light rays entering the
eye. Cornea is a thin membrane covering the surface of eyeball, through which light enters.
Iris – It is a dark muscular diaphragm that controls the size of the pupil.
Pupil: -The black opening between the aqueous humours. And the lens. Since, light does not get
reflected from it the appearance is dark. The amount of light entering the eye is controlled by the size of
the pupil. In dim light it opens up completely through the iris, but in bright light it becomes very small.
Ciliary Muscles: - The Shape of the eye-lens can be modified by the presence of ciliary muscles. This
leads to Variation in focal length.
 When the muscles are relaxed the focal length of the lens has its maximum value, equal to the
distance from to the retina. So parallel rays coming into the eye get focused on the retina.
 The focal length under relaxed state in about 2.5cm. When the eye looks at nearby objects, the
ciliary‟s muscles are strained and the focal length decreases.
Accommodation: - The ability of the ciliary muscles to adjust the curvature and there by the focal
length to get clear view of objects is called accommodation.
Power of Accommodation: - The maximum variation in power of the lens so that the far off and nearby
objects are viewed is called Power of Accommodation – for a person having normal vision. It is about
dioptres.
Near Points of Eye: - The minimum distance between the objects and the eye so that a clear image is
formed on the retina is called the least distance is 2.5cm for human eye.
Far Point of Eye: - The farthest point up to which the eye can see object clearly is called the Far point
of the eye for normal eye, it is infinity.
Cataract: - Due to membrane growth over the lens, the eye becomes ineffective partially or completely.
The image becomes hazy due to the lens becoming milky and cloudy. This problem is called Cataract.
This is corrected by the surgical removal of extra growth.
Myopia or Short-Sightedness: - Inability of the eye in viewing long distance objects. The image in this
case falls before the retina. For every myopic eye there exists a far point beyond which clear image
cannot be seen. Short-Sightedness is caused due to: - (i) excessive curvature in cornea (ii) elongation of
eye-ball. The short-sightedness is corrected by using a concave lens which diverges and shifts the image
to the retina.
Hypermetropia or long-sightedness: - The inability of the eye in viewing the nearby objects. The
image in this case falls beyond the retina. For hypermetropia eye there exists a near point. LongSightedness is caused due to (i) Greater focal length of the lens or (ii) Eye ball becoming smaller. It is
corrected by using a convex lens which converges and shifts the image to the retina from beyond.
Presbyopia: - The Power of accommodation of the eye usually decreases with ageing. For most people,
the near point gradually recedes away this defect is called Presbyopia.
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
It arises due to the gradual weakening of the ciliary‟s muscles and diminishing flexibility of the eye lens.
A person may suffer from both myopia and hypermetropia. Such people often require bifocal lenses. It
facilitates distant vision. The lower part is a convex lens. It facilitates near vision.
REFRACTION OF LIGHT THROUGH A PRISM:- Prism has two triangular bases and three
rectangular lateral surfaces. These surfaces are inclined to each other. The angle between its two lateral
faces is called the angle of the prism.
The peculiar shape of the prism makes the emergent ray bend at an angle to the direction of the incident
ray. This angle is called the angle of deviation. In this case <d is the angle of deviation.
 DISPERSION OF WHITE LIGHT BY A GLASS PRISM: - This phenomenon of splitting of white
light into its constituent seven colours on passing through a glass prism is called dispersion of light.
The cause of dispersion is that different colours of white light having different wavelengths deviate
through different angles on passing through a glass prism. That is why they split on coming out from the
prism along different directions.
When use pars white light through two identical prism held side by side with their refracting edes in
opposite directions; the first prism disperses white light into seven colours and the second prism
recombines the seven colours into white light Thus light emerging from 2nd prism is white.
 ATMOSPHERIC REFRACTION:- Light coming from stars and entering earth‟s atmosphere passes
from rarer to denser layer‟s Therefore, it suffers multiple refractions before reaching the surface of the
earth. This is called Atmospheric Refraction. Some of the phenomena based on atmospheric refraction.
 Stars seem higher than they actually are:- Stars are independent sources of light, situated very far
away from earth. Light a star travels first in vacuum and then enter into earth‟s atmosphere. As optical
density of air increase towards the surface of earth, therefore, light from the star travels from rarer to
denser layers bending every time towards normal. On producing the final refracted ray backwards as
shown in the apparent star position B is higher than the actual star position A.
 Advanced Sunrise and Delayed Sunset: - The sun which is still below horizon appears to rise just
above the horizon on account of at morphemic refraction. The difference in time involved is two
minutes the Sun appears to rise two minutes earlier.
The sun, which has already gone just below the horizon, appears to be just above the horizon on
account of atmospheric refraction. The difference in time involved is two minutes; the sun appears to
set 2 minutes later.

The sun appears oval at sunrise and sunset, but appears circular at noon: - At sunrise and sunset,
the sun is near the horizon. The rays of light from the upper part and lower part of the periphery of the
sun bend unequally on traveling through earth‟s atmosphere. That is why the sun appears oval or
flattened at the time of sunrise and sunset.
At noon, the sun is over head. The rays of light from the sun earth‟s atmosphere normally.
Therefore, they suffer no refraction or passing through earth‟s atmosphere. Hence the sun appears
circular at noon.
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




Stars twinkle, Planets do not: - The stars twinkle at night, because the star light reaching our eyes
increases and decreases continuously due to atmospheric refraction. When the star light reaching our
eyes increases, the star looks dim. Thus the stars go on becoming bright and dim again and again. This
is called the twinkling of stars at night.
Planets appear bigger than the stars as planets are close to earth compared to the stars. A planet can
be considered to be made up of a number of point sources of light. Due to atmospheric refraction,
when some of the point sources look brighter, others appear dimmer. Therefore, on the whole over all
brightness of a planet remains the same always. Hence the planets do not appear to twinkle.
TYNDALL EFECT:- The phenomenon of scattering of light by colloidal particles. The colour of
scattered light depends on the size of the scattering particles.
THE SUN LOOKS REDDISH AT THE TIME OF SUN RISE AND SUNSET:-At the time of
sunrise and sunset, the sun is near the horizon. The rays from the Sun have to travel a much larger part
of the atmosphere reach an observe on earth. Therefore, most of all the colours of sunlight, the colour
scattered least, and red colour enters into our eyes. Hence, the sun appears reddish, both at the time of
sunrise and sunset.
When the sun is nearly overhead, the sunlight has to pass through much smaller portion of Earth‟s
atmosphere. The scattering is much less and the sun looks white.
WHITE COLOUR OF CLOUDS: - Large particles like rain drops dust or ice particles present in the
atmosphere scattered all the wavelengths of light almost equally. Hence the clouds which have
droplets of water scattered all colours equally to give the white appearance. So clouds generally appear
white.
DANGER SIGNALS ARE RED: - The wavelength of red colour is longer among the other colours
of visible spectrum of sunlight.
Red colour is least scattered while passing through the atmosphere and therefore travels large
distance red color can be seen through a large distance. Hence the danger signals make use of red
light.
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Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
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20.
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22.
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24.
25.
26.
27.
28.
29.
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31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
Write the function of crystalline lens of eye.
Name a right sensitive part of an eye where image of an object is formed.
Name the transparent membrane through which light enters the eye.
Define cataract.
Define angle of deviation.
Define angle of prism.
Define Myopia of short sightedness.
Define Hypermetropia of long sightedness.
What is Tryndall effect?
Write the function of Iris.
Name the part of human eye which regulate & control the amount of light entering the eye.
What type of image of an object is formed on the retina?
What type of signals are generated & sent to the brain by light sensitive cells & retina.
Name the muscles of eye which change the curvature of eye lens.
Define the term least power of accommodation in eye.
Define the term least distance of distinct vision.
What is the near point of eye?
Mention the range of vision of normal eye.
Name the lens used to correct the defect Myopia.
What is dispersion of light?
Which type of lens should be used to correct the presbyopia.
Name the lens used to correct the defect “Hypermetropia”.
Name the defect of vision which arises due to decrease in the power of accommodation of the eye with
ageing.
In visible spectrum, which colour has longest wavelength.
What is the value of least distance of distinct vision & the far point of Human eye.
Why does the sky appear blue?
Why does a ray of white light splits up into different colours on passing through a glass prism.
What is Presbiopia? What is its cause?
When white light passes through a prism, which colour of light bends least & which colour the most.
In which direction rainbow is expected to be seen after rainfall in the evening. Draw a diagram to show
the formation of rainbow.
Explain the formation of rainbow.
The Sun appears to be red at the time of sunset & sunrise. Give reason.
Explain the phenomenon which causes twinkling of star.
Why doesn‟t the planet twinkle?
In dispersion of white light through prism, which colour deviates most & which least. Why do they
deviate differently?
On what factors does the colour of the scattered light in Tryndall effect depend?
Why do stars twinkle?
The far point of a myopic person is 80 cm in front of the eye. What is the nature & power of lens
required to correct the problem?
Near point of a hypermetropic eye is at 1 m. Find the focal length, power & nature of lens used to
correct this defect.
With the help of a diagram, explain Myopia. How can we correct it?
Draw a labeled diagram of human eye & explain the working of each part of it.
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Our Environment
Important terms and definitions:
Environment:- It is the sum total of all external conditions and influences that affect the life and
development of an organism, i.e., the environment includes all the physical or abiotic and biological or
biotic factors.
 Biodegradable Substances:- Those substances which are broken down into simpler, harmless substances
in nature with due course of time by the biological processes such as action of microorganisms like certain
bacteria.
 Non-biodegradable Substances:- Those substances which cannot be broken down into simpler, harmless
substances in nature. These substances may be solid, liquid or gaseous form and may be inert and
accumulate in the environment or may be concentrated in the food chain and harm the organisms.
Examples:- DDT, plastics, polythene bags, insecticides, pesticides, mercury, lead, arsenic, aluminium,
radioactive wastes, etc.
 Ecosystem: - It is the structural and functional unit of biosphere, comprising of all the interacting
organisms in an area together with the non-living constituents of the environment. Thus, an ecosystem is a
self sustaining system where energy and matter are exchanged between living and non-living components.
It is therefore associated with the biotic or biological components comprising of living organisms and the
abiotic components comprising of physical environmental factors, e.g., Ponds, Aquarium.
 Biotic component: - It means the living organisms of the environment- plants, animals, human beings and
microorganisms like bacteria and fungi, which are distinguished on the basis of their nutritional
relationship.
 Abiotic component: - It means the non-living part of the environment – air, water, soil and minerals. The
climate or physical factors such as sunlight, temperature, rainfall, humidity, pressure and wind are a part
of the abiotic environment.
 Types of ecosystems:- Ecosystems are of two types:(i) Natural Ecosystems: The natural ecosystems are terrestrial (land) as well as aquatic. The common
examples of land ecosystem are forests, grasslands, deserts, etc. The common examples of aquatic
ecosystem are ponds, lakes, rivers, ocean, etc.
(ii) Human-made or Artificial Ecosystems:- The artificial ecosystems are made by human beings. The
common examples of artificial ecosystems are crop fields, gardens, parks, aquarium, etc.
 Producers:- Those organisms which produce food by photosynthesis, i.e., organisms which can make
organic compounds like sugar and starch from inorganic substances using the radiant energy of the sun in
presence of chlorophyll. Producers therefore are considered as a source of energy for those above it in a
food chain.
Examples:- All green plants also called autotrophs and certain blue-green algae.
 Decomposers:- They are those micro-organisms that obtain energy from the chemical breakdown of dead
organisms or animals or plant wastes. These micro-organisms are the decomposers as they breakdown the
complex organic substances into simple inorganic substances that go into the soil and are used up once
more by the plants.
 Consumers:- Those organisms which depend upon the producers for food, either directly or indirectly by
feeding on other consumers for their sustenance. Consumers therefore feed upon those below it in a food
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chain and are called heterotrophs. It can be classified into primary consumer or herbivores, secondary
consumer or small carnivores, omnivores and parasites.
Herbivores are the animals that consume or eat vegetation or plants, e.g., cows, horses.
Carnivores are the animals that eat meat of other animals, e.g., tigers, wolves.
Omnivores are the animals that eat both plants and animals, e.g., humans, cockroaches.
Parasites are those organisms that live on (ectoparasites) or in (endoparasites) the body of another
organism, i.e., host from which it obtains its nutrients, e.g., parasites of man includes fleas and lice
(ectoparasites) various protozoans (endoparasites) and tapeworms.
 Food Chain:- It is sequence of organisms through which energy is transferred in the form of food by the
process of one organism consuming the other. It shows the relationship of producer and consumer, i.e.,
„who eats whom‟. Thus, it is a series of organisms taking part at various biotic levels from the producer
and ends in consumer.
A simple generalized food chain operating in an ecosystem is as follows:
Producers  Herbivores  Carnivores
Examples of food chains:
i.
Food chain in forest or grassland ecosystems:Grass  Grasshopper  Frog 
Snake

Eagle
(Producer)
(Herbivore)
(Carnivore)
(Carnivore)
(Top Carnivore)
ii. Food chain in aquatic ecosystems:Phytoplankton  Zooplankton  Crustacean  Fish  Crane
(Producer)
(Herbivore) (Carnivore)
(Carnivore) (Top Carnivore)
 Trophic Levels: - These are the various steps or levels in the food-chain where transfer of food or energy
takes place. The producers or autotrophs are the first trophic level, the herbivores or primary consumers
are the second trophic level, the carnivores or secondary consumers are the third trophic level and the
large carnivores or tertiary consumers are the fourth trophic level of the food chain.
 Significance of Food Chain:(i) The study of food chain helps in understanding of food relationships and interactions among various
organisms in an ecosystem.
(ii) With such studies one can follow the basic mechanism of transfer of food energy and nutrients through
various components of nature.
(iii)One can also understand the movement of toxic substances in an ecosystem and the problem of their
biological magnification.
 Food Web: - It is the network of various food chains which are interconnected at various trophic levels.
Since an organism can occupy position in more than one food chain, in a food web it occupies more than
one trophic level.
Example: - Grass may be eaten by grasshopper as well as rabbit or cattle and each of these herbivores may be
eaten by many carnivores such as frog, bird or tiger depending on their food habits.
 Flow of Energy: - The flow of energy through different steps in the food chain is unidirectional. This
means that energy captured by autotrophs does not revert back to the solar input and it passes to the
herbivores. It moves progressively through various trophic levels.
(i) Green plants capture 1% of energy of the sunlight that falls on their leaves and convert it into food
energy.
(ii) When green plants are eaten by primary consumers, a great deal of energy is lost as heat to the
environment. On average 10% of food eaten is turned into its own body and made available for next
level of consumers.
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


(iii) Thus, 10% can be taken as average value, the amount of organic matter present at each step and
reaches the next level of consumers.
(iv) As very less energy is available for next level of consumer, food chain consists of only three or four
steps. The loss of energy at each step is so great that very little energy remains after four trophic
levels.
(v) There a greater number of individuals at lower trophic level i.e., at the producer level of the
ecosystem.
(vi) Therefore, in an ecosystem, the sun‟s energy is then transformed by producers into chemical energy
by the process of photosynthesis.
(vii) In herbivores and carnivores this energy is then transformed further at various trophic levels.
(viii) The chemical energy is transformed into mechanical energy and heat.
(ix) Thus, energy flows from sun through producers to consumers in a single direction only.
(x) So, there is maximum energy at the producer level and further the energy goes on decreasing. The
herbivores get more energy with food than carnivores at third and fourth trophic levels.
Biological Magnification: - It refers to the process of increase in the concentration of a toxic chemical
with increasing trophic level in a food chain.
(i) Harmful or poisonous substance such as DDT sprinkled to kill pests on plants enters the food chain.
(ii) As human beings occupy the top level in any food chain, the maximum concentration of harmful
chemicals gets accumulated in the body, the phenomenon of which is known as biological
magnification.
Accumulation of Harmful Chemicals in Food Chain: - Some poisonous chemicals enter our bodies
through the food chain.
(i) It is by the use of several pesticides and other chemicals for crop protection and storage, etc.
(ii) The plants absorb these harmful chemicals from soil along with water and minerals.
(iii)They enter the food chain in producer level and then transferred to next trophic levels.
(iv) The highest levels get more of these chemicals.
Water  Planktons  Fish
(Aquatic plants and animals)
Ozone: - Ozone (O3) is an isotope of oxygen, i.e., it is a molecule formed by three atoms of oxygen.
UV


O2
O+O
O + O2
O3 (Ozone)
(i) Ozone exists in the so-called ozone layer of the stratosphere.
(ii) Ozone at higher levels of atmosphere is a product of UV radiation acting on oxygen (O2) molecule.
(iii) Ozone performs an essential function of shielding the surface of the earth from ultraviolet radiation of
the sun.
Ozone Layer: - It is a layer of the earth‟s atmosphere in which most of the atmosphere‟s ozone is
concentrated.
(i) Ozone layer protects the earth from harmful radiations like high energy ultraviolet radiations from
passing through it. This property gives it an important function in protecting the biosphere.
(ii) In this layer most of the sun‟s ultraviolet radiation is absorbed by the ozone molecules, causing a rise
in the temperature of the stratosphere.
(iii) The use of chemicals like CFCs has endangered the ozone layer.
Depletion of Ozone Layer:- There are many reasons for depletion of ozone layer
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
(i) The foremost is the use of chlorofluoro-carbons (CFCs). The other factor responsible for ozone
destruction is the pollutant nitrogen monoxide (NO).
(ii) When the harmful chemicals like chlorofluorocarbons (CFC) are released into the air it accumulates
in the upper atmosphere and reacts with ozone resulting in reduction of the ozone layer by forming a
hole.
(iii) This, the ozone layer in the atmosphere becomes thinner and gets depleted allowing more ultraviolet
rays to pass through the earth.
(iv) The Antarctic hole in ozone layer is caused due to chlorine molecules present in chlorofluorocarbons
(CFCs) that are used by human beings.
Garbage Management:(i) More quantity of waste material is generated due to the improvement of our day to day lifestyle.
(ii) Nowadays, more and more disposable items are used due to change in our attitude.
(iii) Changes in packaging have resulted much of our non-biodegradable waste.
(iv) Proper method of garbage by segregating biodegradable, non-biodegradable and recycling material
to be used.
Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
Define environment.
Define consumers.
According to the sustenance from environment, organisms can be grouped into which three categories?
Name any two groups of producers.
Write any one significance of biochemical cycles.
Explicate the principle of food web.
Write the two raw materials for making food, used by living organisms of first tropic level.
Write a common feature between a food chain and energy flow in nature.
Discuss biological magnification.
Why food grains like wheat, rice are harmful for consumption even after they are washed before use.
Can producers use organic compounds as raw material for making food?
As a step to control pollution „kulhads‟ were used on a large scale. What was the ill effect of this
practice?
Which of the two is poisonous: Ozone or carbon dioxide?
Which component of sunlight is vital for formation of ozone?
Which one ill effect of exposure to ultraviolet rays?
A food chain consists of grass, Lion and rabbit. In this food chain which organisms will transfer maximum
energy?
Expand UNEP.
Which is greater- Energy lost to the environment or energy transferred to next tropic level.
How is packaging related to increase in non-biodegradable waste?
Name the programme that froze CFC production in 1986.
Which of the following is Biodegradable: Plastic toys, cowdung, aluminium foil and cotton?
Describe the process of decomposition.
Choose a biotic components comprising physical factors from the following:
Rose, Soil, Leaf, Potato,
Distinguish between biodegradable and non- biodegradable wastes. Give examples.
Why a plastic bag is called non-biodegradable while a paper is not.
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26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
Define an ecosystem. Is the road near your school a part of ecosystem?
Name any four ecosystems.
Differentiate between natural and artificial ecosystem.
A neem tree is a producer but not the bread mould found on bread we eat. Give reasons.
Why decomposers are necessary in environment?
Draw a pyramid showing four trophic levels.
Energy stored in the body of lion is the energy coming from sun. Justify.
Distinguish between food chain and food web.
Pesticides are useful to farmers, yet considered as pollutants. Give reasons.
Enlist two uses of CFCS. Write their harmful effect?
Consider a food chain:Grass → Insect → Frog → Snake →Hawk
How much energy is available at the first tropic level and fifth tropic level?
Describe the 10% law of flow of energy using example. What percentage of solar
energy is captured
by plants in terrestrial ecosystem that falls on their leaves?
A farmer cultivates wheat crop in his agricultural field. Explain the interlinks of Biotic and abiotic
factors in this case.
How are ozone categories of consumers giving examples of each?
Explain how the pesticides used in the field reaches inside the body of a tertiary consumer.
Identify a deadly poisonous gas X found at a higher level of atmosphere which shields the surface of
earth from harmful radiations from the sun. Write its chemical formulation and equation of its formation.
Why is damage to X layer a cause of concern? What steps are being taken to limit this damage?
Make two food chains and a food web from the following set of living organisms: Grass, lion, vulture,
Deer, Insect, and Snake. Identify the tertiary consumer in both of the food chain.
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Management of Natural Resources
 Natural Resources: - It is the stock of the nature such as air, water, soil, minerals, coal, petroleum, forest
and wildlife that are useful to mankind in many ways.
 Pollution: - It is defined as the undesirable change in physical, chemical or biological characteristics of
our soil, air or water, which harmfully affect human lives or the lives of other species.
 Ganga Action Plan: - It is a massive multi-crore project implemented in 1985, which has been
undertaken to clean the excess of pollution from the river Ganga.
 Colifeom: - It is a group of gram-negative rod-shaped bacteria that are found in human intestine. Their
presence in water is an indicator of contamination by disease causing microorganisms causing faecal
pollutions.
 Three R’s to Save the Environment: - We can reduce pressure on the environment by applying the
maxim of „Reduce, Recycle and Reuse‟ in our lives.
 Reduce: The means „to use less‟.
 By switching off unnecessary lights and fans to save electricity.
 By repairing leak taps to save water.
 By not wasting food.
 Recycle: This means to collect plastic, paper, glass and metal items and recycle this material to make
required things.
 In order to recycle, firstly segregation of waste is necessary so that materials that can be recycled
are not dumped along with other wastes.
 Reuse: This means „to use things again and again‟.
 The used envelopes can be reversed and used again instead of throwing away.
 The plastic bottles of food items like jam or pickle can be used for storing things in the kitchen.
 Sustainable Development: - It is the development which can be maintained for a long time without
undue damage to the environment.
 The objective of sustainable development is to provide the economic well being of the present and
the future generations and to maintain a healthy environment and life support system.
 It encourages forms of growth that meet current basic human needs, thus sustainable development
implies a change in all aspects of life.
 It depends upon the willingness of the people to change their perceptions of the socio-economic
environmental conditions and use of natural resources.
 Needs to Mange Our Resources:
 Our natural resources are limited with the rapid increase in human population. Due to improvement
in health care, the demand for all resources is also increasing.
 Management of natural resources requires long term perspective to meet the needs and aspiration of
future generations.
 Natural resources should be managed in such a way that everyone of the society is benefited from
its development.
 The waste generated from exploration of natural resources should be disposed off safely. For
instance, mining causes pollution due to discard of large amount of slag during metal extraction.
 Biodiversity: It is the existence of a wide variety of species of plants, animals and microorganisms in a
natural habitat within a particular environment or of genetic variation within a species.
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 Biodiversity of an area is the number of species or range of different life forms found there.
 Forests are „biodiversity hotspots‟.
 Stakeholders of Forests: The conservation of forests depend on its forest resources or its various
stakeholders, who are as follows:
(i) People who live in or around forests: - It is depend on forest produce, for various aspects of their life.
 The local people need large quantities of firewood, small timber and thatch. Bamboo is used to
make slats for huts and baskets for collecting and storing food.
 Implements for agriculture, fishing and hunting are largely made of wood.
 People collect fruits, nuts and medicines from forests, their cattle also graze in forest.
 By switching off unnecessary lights and fans to save electricity.
(ii) Forest Department of the Government: - which owns the land and controls the forest resources.
 People develop practices to ensure that forest resources are used in a sustainable manner.\
 The forest resources became over-exploited after the British took control of the forest.
 Forest department of independent India then owned the land and control the resources of the forest
but local needs such as herbs, fruits and fodder are ignored.
 Monoculture of pine, teak or eucalyptus have been started which destroys the biodiversity of the
area.
(iii) Industrialist:
 Industrial consider the forest as a source of raw material for its factories.
 These industries are not interested for the sustainability of the forest in one area as they go to a
different area after cutting down all trees in one area.
(iv) Wildlife and Nature Enthusiasts:
 They are not dependent the forest but conserve nature and take part in its management.
 Conservationists started with conserving large animals but now preserving biodiversity as a whole.
 The local people, for instance the Bishnoi community in Rajasthan worked for conservation of
forest and wildlife as a religious act. Thus, management of forest resources has to take into account
the interests of various stakeholders.
 Traditional Use of Forest. An example:
 Alpine grasslands in Himalayas were grazed by sheep in summer.
 Nomadic shepherds drove their flock every summer in this area.
 But when the great Himalayan National Park was formed this practice was put to an end. This
resulted in tall grasses, preventing fresh growth.
 Amrita Devi Bishnoi National Award: In 1731, Amrita Devi Bishnoi sacrificed her life along with 363
persons for the protection of „Khejri‟ trees in Khejrali village near Jodhpur in Rajasthan. In her memory
Government of India have recently instituted this award for „Wildlife Conservation‟.
 Causes of Damages to Forests: Local:
(i) Local people damages forests to fulfil their daily needs.
(ii) Deforestation caused by industrial needs.
(iii) Deforestation caused development projects like building roads or dams.
(iv) By tourists or in making arrangements for tourists.
 Economic Growth and Ecological Conservation:
 Forests resources should be used in an environmentally and developmentally sound manner.
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




 The benefits of controlled exploitation of resources go to the people and the environment is also
preserved.
 If the exploitation is too high, economic and social development will be faster but the environment
will further detoriate.
 We should use natural resources cautiously so that economic growth and ecological conservation go
hand in hand.
Chipko Movement:
 During 1970, in Reni village of Garhwal, a contractor was allowed to cut trees in a forest near the
village.
 When the contractor‟s workers went to the forest to cut trees the woman of the village hug the tree
trunks to prevent the workers from cutting trees.
 Chipko means „hug‟ and the movement started by the villagers by hugging trees is called the
„Chipko Andolan‟.
People Participation in Forest Management. An Example:
 The Sal forests I West Bengal got reduced alarmingly in 1972.
 Surveillance and policing to protect the forest resultfreque3nt clash between forest officials and the
villagers.
 In return, villagers were given employment and were allowed to collect firewood and fodder at
nominal fee.
 By 1983, the Asabari forest showed a remarkable recovery.
Water as Basic Natural Resource:
 It is a valuable national asset
 It is the main requirement of human beings.
 Water is of two types-salt water and fresh water.
 Fresh water is an unlimited natural resources, it can be obtained form three natural resources-rain
water, surface water and ground water.
 Human intervention pollutes water and also changes the availability of water in various regions.
Water Sources:
 Rain in India is due to monsoon.
 Failure to sustain underground water due to loss of vegetative cover, development of water
demanding crop and pollution from industrial effluent.
 Small dams, canals and tanks were used for irrigation purpose and to fulfill the basic minimum
needs.
 Large dams and canals were made by British as well as our own government.
 Due to the mega projects, local irrigation methods got neglected and the local people lost control
over management of local water sources.
Management of Water Resources:
(i) Integrated water-shed plan for drinking, irrigation and industrial uses.
(ii) Flood Control.
(iii) Transfer of surplus water to water deficit basins by inter-linking of rivers.
(iv) Hydro geological survey to identify over-exploited ares.
(v) Artificial recharging of the groundwater.
(vi) Mass awareness programmers through public or private agencies.
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
Dams: - They are massive barriers built across rivers and streams to confine and utilize the flow of wat er
for human purposes such as irrigation and generation of electricity.
 Large dams can also ensure the storage of adequate water.
 Canal system leading from dams transfer large quantity of water great distances, e.g., Indira Gandhi
Canal of Rajasthan brought greenery to considerable.
 Purposes for Building a Dam:
(i) Generation of electricity.
(ii) Irrigation
(iii) Control flooding which either stops or slows the amount of water in the river.
 Criticism about Large Dams:
(i) Social Problems as they displace large number of farmers and tribals.
(ii) Economic Problems as they consume huge amount of public money without proportionate
benefit.
(iii)Environmental Problems as they cause deforestation and loss of biological diversity.
 Mismanagement of Water Distribution: Due to mismanagement in distribution of water, the benefit of
constructing a dam goes to few people only. For example, people close to the source grow water intensive
crop like sugarcane and rice while people farther downstream do not get any water. This resulted in
discontentment among the people who have been displaced by building of dam.
 Traditional Water Harvesting System:
 The water harvesting structures in a largely level terrain are mainly crescent shaped earthen
embankments or low, straight concrete and rubble built across seasonal flooded areas.
 Monsoon rains fill ponds behind the structures.
 The large structure hold water throughout the year while most dry up after monsoon.
 The main purpose of this system is to recharges the groundwater and not to hold surface water.
 Watershed Management: It means scientific conservation of soil and water to increase the biomass
production.
 Watershed management not only increases the production and income of the watershed community
but also overcomes drought and flood.
 It increases the life of downstream dams and reservoirs.
 Water Harvesting: It means capturing rainwater where it falls or capturing the run off in a local area and
taking measures to keep the water clean by not allowing polluting activities to take place.
 Benefits of water Harvesting:
 Provide drinking water.
 Provide irrigation water.
 Increase in groundwater resources.
 Reduces storm water discharge, urban flood and overloading of sewage treatment plants.
 Advantages of Groundwater:
 It does not evaporate.
 It spreads out to recharge wells.
 It provides moisture for vegetation.
 It does not provide breeding grounds for mosquitoes.
 It is relatively protected form contamination by human and animal waste.
Ques: Define the term „Conservation of environment‟.
Ques: Why is it necessary to conserve our environment?
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Ques: Suggest any tow ways to strike a balance between environment and development.
Ques: What is sustainable development? Suggest any one method to achieve it.
Ques: List any four practices which help in protecting our environment.
Ques: Why is conservation of wildlife considered important for us? Give any two reasons.
Ques: Industrialization is one man cause of deterioration of environment. Discus.
Ques: Replenishment of forests is essential. Justify the statement by giving any three reasons?
Questions
1. Why are molecular movements needed for life?
2. Define life processes.
3. What are the different types of Nutrition Explain then?
4. Draw cross-section of leaf?
5. Write the main step of photosynthesis?
6. Show by an activity CO2 and light is essential for photosynthesis?
7. Explain the opening and closing of stomata.
8. From where plants get its materials and what is use of Nitrogen in them.
9. Give difference in nutrition in amoeba and paramecium.
10. Draw Human alimentary canal.
11. Write the functions of saliva, liver pancreas large intestine, small intestine Enzymes, HCL, Mucus, pepsin,
Lipase, Tripsine, Sphincter, muscle, Bile juice, villi.
12. How can a show that CO2 is the by product of Respiration.
13. Write the pathways of Respiration.
14. Write the mechanism for breath.
15. Draw Human respiration system.
16. Define residual volume and what the function of it is.
17. What is the role of Respiratory pigment?
18. Draw human heart and explain it.
19. Explain circulation of blood in our body.
20. What is the role of septum in different organism?
21. What B role of platelets.
22. Give difference b/w lymph and blood.
23. Give difference b/w xylem and phloem.
24. Explain the transportation of water in plants.
25. How sugar stored in root or stem transported.
26. Human Excretory system and Explain it.
27. Explain the mechanism of urine formation.
28. What are the different ways by which plants excrete?
29. Define control and coordination.
30. Draw structure of neuron and neuromuscular junction.
31. Explain the general scheme of nervous impulses travel in the body.
32. What is Reflex are and Reflex action, Draw it.
33. What are the types of control and coordination in human Nerves & Hormonal?
34. Give difference b/w control by hormones and control by nerves.
35. Draw human brain and live the function of each part.
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36. What is tropism and stimulus?
37. What do you mean by + and – tropism like.
38. Define chemotropism, hydrotropism, phototropism and geotropism.
39. What is the need of Hormones in human body?
40. Write the role of each plant and animal Hormones.
41. Discuss the role of adrenaline is our body.
42. Draw Endocrine glands in human beings.
43. What is the role of sex hormones?
44. What is a Feedback mechanism? Ex & destination.
45. What is the use of Reproduction variations that Create evolution.
46. What is the cause of Variation?
47. Give difference in fission in Amoeba and Leishmania.
48. Multi cellular organisms need to use more complex ways of reproduction. Explain End of asexual.
49. Write a short note on Regeneration and Budding.
50. Explain vegetative propagation, its advantage and disadvantage.
51. Name the non-reproductive part of rhizopus hypae.
52. Give difference b/w a sexual and sexual reproduction. Which one is better in term of variation?
53. Draw L.S of flower and ovary.
54. Give difference b/w female and male germ cell.
55. What are the difference b/w cross and serf pollinated.
56. Draw and explain seed of a dicot plant.
57. What is puberty? What down common sign of puberty in boys and girls.
58. Draw male reproductive system and explain function of each organ.
59. What are the components of serum?
60. Draw female Reproductive system and Explain function of each organ.
61. What is placenta and write their uses.
62. What happens when the egg is not fertilized?
63. What do you mean by STDs write two viral and two bacterial STDs what are their common systems.
64. Explain various birth control methods and mention how they prevent pregnancy.
65. Define Heredity and Variation.
66. What do you mean by inherited and acquired trait?
67. What is the role of Iodine in our body?
68. What are the tools for tracing evolutionary relationships?
69. Define Evolution and fossils.
70. Evolution should not be equated with “progress” Explain.
71. Evolution is a step wise process. Explain.
72. Name two vertebrate and two invertebrate fossils.
73. How can a determined age of fossils.
74. What are the major difference b/w wing of bird and bat?
75. Give difference b/w Homologous and analogous.
76. Define Characteristics.
77. Evolution and classification are interlinked.
78. What was the contribution of Darwin and Mandel?
79. Explain Sex determination Humans.
80. How can you show that traits may be dominator recessive?
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81. Name an organism in which sec determination is not controlled by genes.
82. Discuss Law of Independent inheritance.
83. How do traits get expressed?
84. Discuss same visible contrasting characters in pea.
85. How characteristics being used to determine how two species are in evolutionary Terms.
86. What evidence do we have for the origin of life from inanimate?
87. What are the various observations which help as to determine whether a chemical Rxn take place or not.
88. Define word equation.
89. How can you write a balanced chemical equation?
90. Define Exothermic and Endothermic Rxn.
91. Define combination, Decomposition, photochemical Displacement and Double Displacement Rxn
precipitation Rxn.
92. Explain Electrolysis of water?
93. Write an equation which is not Redox.
94. Define oxidizing and Reducing Agent.
95. Explain the ex. Of common oxidation in our daily life.
96. Define Reduction and oxidation.
97. Define Indication Explain and classify them.
98. What do you mean by water of crystallization? How can you show that P.O.P contains water of
crystallization?
99. Write the uses of washing soda, baking soda. P.O.P and Bleaching powder.
100. Draw a flow chart which shows different product and their uses by chlor-alkali process.
101. What do you mean by salts classify them.
102. What is PH of Acid Rain and our mouth at which Decay of tooth start.
103. Draw and Explain PH scale.
104. Define dilution and Explain effect of dilution of PH on Acid and Base.
105. Explain by an Activity effect of metal an acid and Base, Rxn of metal carbonate and metal hydrogen
carbonate with acids.
106. How can you show that acid and Base produced ions in their solutions.
107. The acid must always be added slowly to water. Why.
108. Prepare a Soda-acid fire extinguish wisher.
109. Show by an Activity: - (a) Metal is good conductor of heat, (b) Electricity, (c) Metal salt can electricity.
110. Define malleability and ductility, luster.
111. Give difference b/w physical properties of metal and non-metal.
112. H2 is not evolved when metal reacts with HNO3
113. Define Reactivity series of metal.
114. Explain the bond-formation of NaCl.
115. Give difference b/w Ionic compound and covalent bond
116. Give difference b/w Ionic compound and covalent.
117. Draw an outline which shows metallurgy of low.
118. Give difference b/w calcinations and roasting.
119. Define minerals and ore, gangue.
120. Explain the metallurgy of Zn.
121. Draw and Explain Electrolytic refining and electrolytic Reduction.
122. Show by an activity that Rusting needs H2O and O2 both
123. Define Alloys How and why they are formed.
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Name the bacteria whose presence in the water indicates its contamination with disease causing
microbes.
Define sustainable development.
Name the award recently instituted by govt. of India in the memory of Amrita Devi Bishnoi.
Why fossil fuels should be used judiciously?
Which canal has brought greenery to the areas of Rajasthan?
State the advantages of constructing a dam across a river.
Write the main aim of conservation of different life forms?
Define Bio-Diversity.
What do you mean by water-shed management?
What is a natural resource?
Name two important natural resource?
What do the three R‟s stand for to save the environment?
Name the gas responsible for global warming.
Name the main constituents of coal and petroleum.
The forest department is managing the forests in India. How does this management affect the people
living in and around forest?
How human activities cause damage to forests?
Name any two indegeous method for water harvesting.
Give an example of people‟s participation in the management of forest.
Which is better recycle or reuse. Give reasons.
What is necessary to conserve forest and wildlife?
A tribe is living near the forest. Name two things which they will commonly use from forest.
Name the products of combustion of coal and petroleum. How do they affect our environment?
Write the aims and two advantages of water shed management.
State two disadvantages of constructing a dam across the river.
What is water harvesting? What is the main purpose of water harvesting?
Name the main stakeholders in the management of forest resource.
Name the major industries based on forest producer.
“Save the Narmada movement” activists are protesting to certain problems. What are those problems?
Mention three ways to reduce the consumption of coal and petroleum.
Explain 3R‟s with one example of each.
Write main uses of fossil fuels.
What are the disadvantages of water stored in ground?
In India monsoon is a plenty but still there is a failure to sustain water availability. Give reasons.
(i) Write the poisonous by-products of combustion of coal and petroleum.
(ii) Give ways in which you can contribute towards environment friendliness.
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