Set - B
MT EDUCARE LTD.
CBSE - X
SUMMATIVE ASSESSMENT - II
(2015-16)
Set - B
Code No.
Roll No.
32/1
Series RLH
•
Please check that this question paper contains 6 printed pages.
•
Code number given on the right hand side of the question paper should be
written on the title page of the answer-book by the candidate.
•
Please check that this question paper contains 36 questions.
•
Please write down the serial number of the question before attempting it.
SCIENCE (Theory)
Time allowed : 3 hours
Maximum Marks : 90
General Instructions :
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
x)
The question paper comprises of two sections, A and B, you are to attempt both the
sections.
All questions are compulsory.
There is no choice in any of the questions.
All questions of section-A and all questions of section-B are to be attempted
separately.
Question numbers 1 to 3 in section-A are one mark questions. These are to be
answered in one word or one sentence.
Question numbers 4 to 6 in section-A are two marks questions. These are to be
answered in about 30 words each.
Question numbers 7 to 18 in section-A are three marks questions. These are to
be answered in about 50 words each.
Question numbers 19 to 24 in section-A are five marks questions. These are to
be answered in about 70 words each.
Question numbers 25 to 33 in section-B are multiple choice questions based on
practical skills. Each question is a one mark question. You are to select one most
appropriate response out of the four provided to you.
Question numbers 34 to 36 in section-B are questions based on practical skills.
Each question is a two marks question.
... 2 ...
Set - B
SECTION - A
1.
Name the gas evolved when ethanoic acid is added to sodium carbonate.
1
2.
How does reproduction help in providing stability to the population of
species ?
1
3.
If the radius of curvature of a spherical mirror is 20 cm, what is its focal
length ?
1
4.
What is water harvesting ? What is the main purpose of water harvesting ? 2
5.
Give the common name and IUPAC name of C2H5OH.
2
6.
The far point of a myopia person is 150 cm.What is the nature and the
power of lens required to correct the defect?
2
7.
Define substitution reaction. What happens when methane reacts with
chlorine ? Give equation of the reaction which takes place.
3
8.
A neutral organic compound X of molecular formula C2H6O on oxidation
with acidified potassium dichromate gives an acidic compound Y.
Compound X reacts with Y on warming in the presence of conc. H 2SO4 to
give a sweet smelling substance Z. What are X, Y and Z ?
3
State Dobereiner’s law of triad. A, B, C are elements of a Dobereiner’s triad.
If the atomic mass of A is 7 and that of C is 39. What should be the atomic
mass of B ?
3
9.
10. (a) Draw the structure of propanone.
(b) Write the IUPAC name of the following :
(i) CH3 – CH2 – Br
(ii) CH3COOH
11. (a) What is binary and multiple fission ? Name the organisms in which
they occur.
(b) What is fragmentation ?
12.
(a) Explain the term : Placenta
(b) What is the average duration of human pregnancy ?
13. (a) What is genetic drift ?
(b) What is gene flow ?
1
2
2
1
2
1
2
1
Set - B
... 3 ...
14. A convex lens of focal length 40 cm and a concave lens of focal length
50 cm are placed in contact with each other. Calculate the (a) power,
and (b) focal length of this lens combination.
3
15. Suggest reason for each of the following :
(a) The sky near the horizon appears to have a reddish colour at the time
of sunset and sunrise.
(b) The sky appears dark instead of blue to an Astronaut in space.
(c) Stars appear to twinkle.
3
16. (a) A concave mirror produces three times enlarged image of an object
placed at 10 cm. in front of it. Calculate the focal length of the mirror.
(b) Show the formation of the image with the help of a ray diagram when
object is placed 6 cm away from the pole of a convex mirror.
3
17. Why must we conserve our forests ? List any two causes of deforestation
taking place.
3
18. What are trophic levels ? Give an example of a food chain and state
the different trophic levels in it.
3
19. (a)
Li
Be
B
C
N
O
F
Na
Mg
H
Si
P
S
Cl
Given above is a part of the periodic table :
As we move horizontally from left to right :
(i)
What happens to the metallic character of the elements ?
(ii) What happens to the atomic size ?
(b) The elements X, Y and Z belong to group 2, 14 and 16 respectively,
of the periodic table.
(i)
Which 2 elements will form covalent bond ?
(ii) Which 2 elements will form an ionic bond ?
3
2
20. (a) State the changes that occur in human males at puberty.
(b) In human body what is the role of :
(i) Seminal vesicles
(ii) Prostate gland.
(c) List two functions performed by testes in human beings.
1
2
21. What are various evidences in factors of evolution ?
5
22. (a) Who is known as the “father of Genetics”?
(b) What is microevolution ?
(c) What is evolution ?
1
2
2
2
... 4 ...
Set - B
23. Name the type of mirror that should be used to obtain :
(i) a diminished and virtual image of an object.
(ii) a magnified and virtual image of an object.
Justify your answers with suitable ray diagram.
5
24. (a) State the Laws of refraction.
(b) A ray of light enters from a medium A into a slab made up of a
transparent substance B (as shown in figure). Refractive indices of
medium A and B are 2.42 and 1.65 respectively. Complete the path of
ray of light till it emerges out of the slab.
5
Medium A
Medium B
SECTION - B
25. A soap molecule has a :
(a) hydrophilic head and hydrophobic tail
(b) hydrophobic head and a hydrophilic tail
(c) hydrophobic head and a hydrophobic tail
(d) hydrophilic head and a hydrophilic tail
1
26. The fuel which usually burns with a blue flame is
(a) Coal
(b) LPG
(c) Candle wax
(d) Kerosene
1
27. The hydrocarbon which has alternate single and double bonds arranged
in the form of a ring is :
(a) cyclobutane
(b) benzene
(c) butene
(d) hexene
1
28. A student determines the focal length of device X, by focusing the image of
a far off object on the screen positioned as shown in the figure below :
Set - B
... 5 ...
The device X is a :
(a) Convex lens
(c) Convex mirror
(b)
(d)
Concave lens
Concave mirror
29. After performing the experiment for determining focal length of a concave
mirror by focussing a distant object on a screen, the teacher asked
students to describe the nature, size and position of image. Their replies
were studied and classified in four groups as :
(a) Image is virtual, inverted, smaller in size
(b) Image is real, inverted, smaller in size
(c) Image is virtual, erect, smaller in size
(d) Image is real, erect, smaller in size
Correct response are classified in :
(A) a
(B) b
(C) c
(D) d.
1
1
30. Parallel rays from a distant object incident on a convex lens form an image
on the screen.
The focal length of the convex lens in the experimental set up is :
(a) 5.4 cm
(b) 6.4 cm
(c) 4.5 cm
(d) 4.6 cm
1
31. The type of reproduction taking place is
(a) Budding
(c) Regeneration
(b)
(d)
Fragmentation
Fission
32. For the experiment –
To prepare temporary mount of yeast to study budding process;
Yeast granules are made to first grow by adding them to :
(a) Hydrochloric acid
(b) Distilled water
(c) 10% sugar solution
(d) Alcohol
1
1
Set - B
... 6 ...
1
33. Identify the organism
(a) Rhizobium
(c) Rhizoid
(b)
(d)
Rhizopus
Mushroom
34. (i) How can we know how old fossils are :
(a) Fossils found closer to surface are recent than those found much
below
(b) Detecting ratios of isotopes
(c) Studying its characteristics
(d) All of them
(ii) Which of the following is controlled by genes ?
1. Weight of a person
2. height of a person
(a) only 1
(b) only 2
(c) both 1, 2
(d) Sometimes 1 and sometimes 2
35. A person walking in a dark corridor enters into a brightly lit room.
(a) State the effect on the pupil of the eye.
(b) How does this affect the amount of light entering the eye ?
1
1
2
36. A concave lens of focal length 15 cm forms an image 10 cm from the lens.
How far is the object from the lens ?
2
All the Best

Set - B
MT EDUCARE LTD.
CBSE X
SUBJECT : SCIENCE
Set - B
Marks : 90
SUMMATIVE ASSESSMENT - II
Date :
MODEL ANSWER PAPER
Time : 3 hrs.
SECTION - A
1.
Carbondioxide (CO2)
1
2.
Stability is provided by equalizing the birth and death ratio. Thus,
the rate of birth should approximately be equal to the rate of death.
1
3.
f=
4.
(i) Rain water harvesting is collecting the rain water, allowing it to
percolate, discharge down the earth and increase the ground water
level.
(ii) It is done to manage water. Tals in Maharashtra is an example of
traditional system of water harvesting management.
2
5.
Common name – ethyl alcohol
IUPAC name – ethanol
2
6.
u =  ,v = -150 cm
Using lens formula,
1 1 1
1
1
1
  

  f  150cm  f  1.5 m
f
v u
f
150 
7.
R
2
 f=
20
2
1
 f = 10 cm
1
1
10


 0.66D
f
 1.5 15
Power of lens:
P
Nature of lens:
Concave.
2
The reaction in which hydrogen atoms of a hydrocarbon are replaced by
some other atoms is called a substitution reaction.
Methane reacts with chlorine in the presence of sunlight to form
chloromethane and hydrogen chloride.
CH4
methane
sunlight
+ Cl2 
 CH3Cl
Chlorine
Chloromethane
+
HCl
Hydrogen chloride
3
Set - B
... 2 ...
8.
9.
X is ethanol
Y is ethanoic acid
Z is ethyl ethanoate
3
‘When the three elements in a triad are written in the order of increasing
atomic masses, the atomic mass of the middle element was roughly the
average of the atomic masses of the other two elements’.
Atomic mass of A = 7
Atomic mass of C = 39
Arithmetic mean of atomic =
mass of A and C
7  39
2
46
2
= 23
= 23
=
Atomic mass of B
10.
O
(a)
CH3
C
CH3 OR H
3
H
O
H
C
C
C
H
H
H
(b) (i) Bromoethane
(ii) Ethanoic acid
11.
12.
13.
(a) Binary fission is the division of one parent cell into two identical
daughter cells. It takes place in amoeba, paramoecium, euglena and
other protozoa.
In Multiple fission one single celled organism divides into many
daughter cells within a cyst. These are released when the cyst breaks.
This takes place in amoeba, Plasmodium (malarial parasite).
(b) Fragmentation is the method of breaking up of an organism into
smaller pieces or fragments which grow into new organisms as in algae
Spirogyra.
3
2
1
(a) Placenta : It is a special tissue in the form of a disc which is embedded
in the uterus wall. It provides large surface area for glucose and oxygen
to pass from mother to the embryo. The waste generated by the embryo
also passes into the mother’s blood through this placenta.
(b) It takes nine months for the human pregnancy.
2
1
(a) Accidents in small populations can change the frequency of some
genes in a population even if they give no survival advantage. This is
genetic drift, which provides diversity without any adaptations. So, it
is the random change in the frequency of alleles in a population over
successive generations.
2
... 3 ...
Set - B
(b) It is the exchange of genetic material by interbreeding between
populations of the same species. Gene flow increases the variations
in a population.
14.
1
Power of convex lens :
(P1 )  
Power of concave lens :
(P2 ) 
1
1

  2.5 D
f(m)
0.4(m)
1
1

 2 D
f(m) 0.5(m)
Power of combination :
P  P1  P 2
 2.5 D  2D  0.5 D
Focal length of combination :
f 

1
Power of Combination
1
 2 m
0 .5 D
15. (a) At sunrise and sunset light has to pass through thicker layers of air
and large distance. Shorter wavelengths are scattered away only larger
wavelengths of light reaches us.
(b) No atmosphere, no scattering of light.
(c) Due to atmospheric refraction of star light and physical conditions of
earth’s atmosphere not being stationary.
16. (a) u = -10 cm
v = 3u
v = –30
1 1 1
+ =
v u f
1
1
1
+
=
-30 -10 f
1
1 1
=
-30 10 f
1 -1- 3
=
f
30
1 -4
=
f 30
3
3
Set - B
... 4 ...
f=
-30
4
 f = –7.5 cm
(b)
3
17. We must conserve our forests as they are very useful.
(i) They conserve soil by preventing soil erosion, prevent floods and hold
lot of water, maintain ground level of water and bring rainfall.
(ii) They provide lot of raw materials for many industries like timber, sal,
wood, tendu leaves (bidis), coir etc.
Two causes of deforestation :
(a) Exploitation by industries.
(b) Due to increase in population, lot of forest land is converted to
build roads and dams for the infrastructure development.
Pressure of human settlement is also a major cause.
3
18. The various levels or stages in a food chain at which the transfer of food
takes place is called trophic level. An example of food chain is :
Grass  Grass hopper  frog  snake
Grass
Grasshopper
Frog
Snake
–
–
–
–
producer
Primary Consumer (Herbivores)
Secondary Consumer (Carnivores)
Tertiary Consumer (Carnivores)
–
–
–
–
first trophic level
second trophic level
third trophic level
fourth trophic level
3
19. (a) (i) Metallic character decreases as we move horizontally from left to
right.
(ii) Atomic size decreases as we move horizontally from left to right.
(b) (i) Y and Z will form co-valent bond.
(ii) X and Z will form ionic bond.
3
20. (a) Puberty is the state of sexual maturity in humans. The changes that
take place in males during puberty are growth of hair on the body,
appearance of beard and moustache and the voice becomes hoarse.
(b) Seminal vesicles : Produce a fluid which makes the transport of sperms
in it easy.
1
2
Set - B
... 5 ...
Prostate gland : Produce a fluid which keeps sperms floating in it
and provides nourishment.
(c) Two function of testes.
(i) They secrete hormone testosterone responsible for the male
characteristics.
(ii) It helps in the formation of male germ cells called sperms.
21. Evidences are :
1. Homologous organs : Organs which have same structures but different
functions. e.g. wings of a bat, hands of man, limbs of monkey.
2. Analogous organ : Organs which perform similar functions but are
structurally different are called analogous organ. e.g. wings of bat, insects,
birds.
3. Vestigial Organs : These organs are those which appear in an organism
but are functionless e.g. vermiform appendix, nictitating membrane in
eye is present in human beings but has no function.
4. Embryological evidence : The study of embryos of vertebrates shows that
all of them have the same origin as their structures at initial stage are
same. e.g. embryo of frog, fish, man, etc.
5. Fossils as evidence : Archaeopteryx fossil shows a link between reptiles
and birds as this fossil has some features of a bird and some of a reptile.
22. (a) G.J. Mendel is called the “father of Genetics”.
(b) (i) Microevolution is the evolution that takes place on a relatively
small scale at the population level and can change the common
characteristics of particular species.
(ii) But the change is significant.
(c) (i) Evolution is the sequence of gradual changes which take place in
living organisms over millions of years to give rise to new species.
(ii) Evolution is a change in the genetic composition of a population.
(iii) Evolution is the generation of diversity and the shaping of the
diversity by environmental selection.
23. (i) Convex mirror:
M
A
A'
B
P
B' F
N
C
2
2
5
1
2
2
Set - B
... 6 ...
(ii) Concave mirror:
A'
B
C
F
B
P
B'
5
24. (a) Laws of Refraction :
i. The incident ray, the normal and the refracted ray, all lie in a
plane.
ii. The ratio of the ‘sine’ of the angle of incidence to the ‘sine’ of
the angle of refraction is a constant, i.e.,
(b)
sini
= constant, for
sinr
the light of a given colour and for the given pair of media.
5
SECTION - B
25. (a) hydrophilic head and hydrophobic tail
1
26. (b) LPG
1
27. (b) benzene
1
28. (d) Since the rays from distant object are shown to coverge after reflection
the device X to be the concave mirror.
1
29. (b) Image is real, inverted and smaller in size.
1
30. (c) f = 6.5 – 2 = 4.5 cm.
1
... 7 ...
Set - B
31. (c) Regeneration
1
32. (c) 10% sugar solution
1
33. (b) Rhizopus
1
34. (i) (d) All of them
(ii) (b) only 2
1
1
35. (a) Pupil becomes smaller
(b) Amount of light entering the eye is reduced.
2
36. In this question, we have to calculate the object distance u.
Here,
Object distance, u = ?
(To be calculated)
Image distance, v = –10 cm
(To be left of concave lens)
And,
Focal length, f = – 15 cm
(It is a concave lens)
Now, putting these values in the lens formula :
We get :
1 1
–
v
u
=
1
f
1
1
–
–10 u
=
1
–15
–
1
u
=
–
–
1
u
=
–2  3
30
–
1
u
=
1
30
1
1
+
15 10
Object distance, u
=
– 30 cm
Thus, the object is placed at a distance of 30 cm from the concave lens.
The minus sign with object distance shows that the object is on its left
side.

2