Target Publications Pvt. Ltd.
Science and Technology
BOARD ANSWER PAPER : MARCH 2015
SCIENCE AND TECHNOLOGY
SECTION A
1.
(A)
(a)
Rewrite the following statements with suitable words in the blanks:
i.
The device used for producing electric current is called a generator.
[1]
ii.
Stratosphere, the second layer of the atmosphere reaches 48 km above the earth’s
surface.
[1]
(b)
Rewrite the following table so as to match the second column with the first column: Column A
i. eosin
ii. oxidation
2.
2
1
Column B
synthetic indicator
losing hydrogen
[1]
[1]
(c)
CaOCl2
[1] (B)
Rewrite the following statements by selecting the correct options:
i.
(A) When phenolphthalein is added to NaOH, the colour of the solution will become
colourless.
[1]
ii.
(D)
If the potential difference across the ends of a conductor is 220 V and the resistance
of the conductor is 44  (ohm), then the current flowing through is 5 A.
[1]
iii.
(B)
1 A = 103 mA
[1]
iv.
(B)
The distance between principal focus and optical centre of the lens is focal length.
[1]
v.
(B)
When rays of light are incident on a glass slab, then the incident ray and emergent
ray are parallel to each other.
[1]
Answer any five of the following:
i.
a.
Scattering of light depends upon the particle size and wavelength of the light.
b.
In the visible range of light, the fine particles of blue light are scattered more relative to red.
c.
Red light has greater wavelength than the blue light.
d.
As red light is scattered the least by atmosphere, it can travel larger distance.
[½]
[½]
[½]
[½]
ii.
[2]
CuO + 2HCl  CuCl2 + H2O
Copper
chloride
Water
iii.
Newlands’ Octaves law states that “When the elements are arranged in an increasing order of
their atomic masses, the properties of the eighth element are similar to the first.”
[2]
iv.
1 = 3  108 m/s
2 = 1.5  108 m/s
To find: 12

Formula: 12 = 1
2
From Formula,
3108
=2
12 =
1.5108
The refractive index of the medium with respect to air is 2.

Given:
[1]
[1]
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Target Publications Pvt. Ltd.
Board Answer Paper: March 2015
v.
a.
b.
c.
d.
Resistances in series
The voltage across each resistor is different.
The current through each resistor is the
same.
This combination is used to increase the
effective resistance of the circuit.
This combination decreases the current in
the circuit.
Resistances in parallel
The voltage across each resistor is same.
The current in various resistors are
inversely proportional to the resistances.
This combination is used to decrease the
effective resistance of the circuit.
This combination increases the current in
[2]
the circuit.
vi.
A
B1
C
B
F
P
A1
Object (AB) between centre of curvature and focus
Image (A1B1) beyond centre of curvature, real, inverted and magnified.
3.
[2]
Answer any five of the following:
i.
The role of citizen in pollution control:
a.
Citizens should plant trees and develop gardens, parks and open grounds in the locality.
b.
Citizens should save fossil fuels and reduce pollution.
c.
They should minimize electricity consumption.
d.
They should use public transport instead of private vehicles.
e.
Citizens should use non-conventional source of energy like solar, wind energy, tidal energy.
f.
They should maintain vehicles in well tuned condition.
g.
Citizens should keep home and public places clean and should keep their own locality
free from pollution.
[Any six points - ½ mark each]
ii.
a.
b.
The band of coloured components of a light beam is called as spectrum.
[1]
White light is composed of seven colours. When white light is incident a prism, it splits
up into its constituent colours.
[1]
c.
Each colour bends through different angles with respect to incident ray. So the rays of
each colour emerge along different path and become distinct.
[1]
Hence, we get a spectrum of seven colours when white light is dispersed by a prism.
iii.
a.
b.
2
The four most common electrical appliances based on heating effect of electric current
are electric iron, electric heater, electric toaster and electric oven.
[2]
Finely heated platinum wire is used in surgery for cutting tissues much more efficiently
than a knife.
[1]
Target Publications Pvt. Ltd.
iv.
a.
Science and Technology
Gypsum is obtained on mixing Plaster of Paris with water.
2CaSO4.H2O + 3H2O  2CaSO4.2H2O + Heat.
Plaster of Paris
b.
c.
Water
[1]
Gypsum
Gypsum is used as a raw material in manufacturing cement.
[1]
POP is used in making statues and decorating roofs. It is also used in hospitals for
supporting fractured bones.
[1]
v.
Metals
Mg, Hg
vi.
Non-metals
C, S
Metalloids
Si, As
a.
12  + 2.5  + 2.5 
b.
4
4
c.
2
=
=
[3]
[1]
17
[1]
2
2
=
[1]
3
2
4.
Attempt any one of the following:
i.
a.
Short circuiting takes place if a live wire and a neutral wire come in direct contact or
touch each other.
b.
During a short circuit, the resistance of the circuit becomes very small.
c.
A huge amount of current flows through the circuit during a short circuit.
d.
The flow of a large amount of current in the circuit beyond the permissible value (of
current) is called overloading. It may cause fire.
e.
The effects of overloading can be avoided by not connecting many appliances (especially
of high power rating) at a time in the circuit.
ii.
a.
b.
c.
d.
e.
Negative power indicates that 8 students use spectacles having concave lens.
Positive power indicates that 2 students use spectacles having convex lens.
Generally, most of the students use the spectacles having concave lenses of suitable focal
length.
Most of the students suffer from myopia or near-sightedness.
Two possible reasons for myopia:
1.
The ciliary muscles are unable to relax sufficiently.
2.
Increase in the distance between eyelens and retina due to lengthening of eyeball
or curved lens.
[1]
[1]
[1]
[1]
[1]
[1]
[1]
[1]
[1]
[½]
[½]
SECTION B
5.
(A)
(a)
(b)
Find the correlation in the given pair and rewrite the answer:
i.
Tinning : Tin :: Galvanizing : Zinc.
ii.
Mammals : Reptiles :: Amphibia : Fishes.
[1]
[1]
State True or False:
i.
True
ii.
False
iii. True
[1]
[1]
[1]
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(B)
6.
Board Answer Paper: March 2015
Rewrite the following statements by selecting the correct options:
i.
(A) The molecular formula of acetic acid is CH3COOH.
[1]
ii.
(C)
Carbon dioxide enters into the leaves through tiny pores present on the surface of
the leaf called stomata.
[1]
iii.
(A)
CuSO4 solution is blue in colour.
[1]
iv.
(D)
Yeast reproduces by budding.
[1]
v.
(B)
Raisins put in water absorb water by the process of osmosis.
[1]
Solve any five of the following:
i.
a.
Common salt has high melting point and boiling point because there is a strong force of
attraction between the oppositely charged ions.
[1]
b.
So a large amount of heat energy is required to break this force of attraction and to melt
or boil the common salt.
Thus, common salt has high melting point and boiling point.
[1]
ii.
The pancreas with their associated structures:
Gall bladder
Bile duct
Common duct
Pancreatic duct
iii.
a.
[2]
Pancreas
Connecting link between Peripatus and Annelida:
Segmental nephridia, thin cuticle and parapodia like appendages.
Connecting link between Peripatus and Arthropoda:
Trachea and open circulation.
b.
iv.
Stomach
Two plant hormones and their functions:
a.
Gibberellins: Help in growth of stem
b.
Cytokinins: Promote cell division
b.
c.
Toilet soap
High quality of fats and oils are used as raw
material.
Expensive perfumes are added.
During the manufacturing process, special care
is taken to ensure that toilet soaps do not
contain free alkalies which are harmful to skin.
Laundry soap
Cheaper quality of fats and oil are used
as raw material.
Cheaper perfumes are added.
During the manufacturing process free
alkali are added for cleaning action.
[Any two points :1 mark each]
vi.
4
[1]
[1]
[1]
v.
a.
[1]
Objectives of sustainable development are :
a.
Reduce pollution by using eco-friendly technology.
b.
Restrain the use of natural resources to ensure availability for the future generation.
c.
Protection of environment.
d.
Social equality in accessing resources.
e.
Continuous economic growth.
f.
It protects environment by effective handling of waste materials.
g.
It reduces the cost of production.
[Any four points :½ mark each]
Target Publications Pvt. Ltd.
7.
Science and Technology
Answer any five of the following:
i.
Alloy:
a.
An alloy is a homogenous mixture of two or more metals or a metal and a non-metal in
definite proportion.
b.
Alloys do not corrode easily.
[1]
Example:
a.
Brass (copper and zinc)
[1]
b.
Bronze (copper and tin)
[1]
Cells that assist the neuron in their function  Neuroglia
The small gap between the consecutive neurons  Synapse
The small gap between the consecutive neurons  Forebrain (Cerebrum)
ii.
a.
b.
c.
iii.
Fertilization:
a.
During the process of fertilization, sperms enter through the vaginal passage, travel
upwards and reach the oviduct.
b.
In oviduct, one of the sperm fuses with egg and the fertilization is completed.
[1]
Development:
a.
After fertilization, the egg cell (zygote) begins to divide and redivide to form a ball of
cells called a blastocyst.
b.
This blastocyst implants itself in the wall of the uterus.
c.
The embryo develops inside the uterus. It obtains all the nutrients and oxygen from its
mother’s blood through the umbilical cord.
d.
Development of the foetus takes place for nine months.
[1]
Birth:
a.
Nine months onwards, the baby is ready to take birth. It begins to move down towards the
vaginal passage.
b.
During birth, the cervix gradually opens and the baby is released through the vagina.
[1]
iv.
Vestigial organs:
Vestigial organs are the non-functional organs in some organisms but have essential functions
in other organisms.
[1]
Examples of vestigial organs in human beings: Vermiform appendix, wisdom teeth.
[1]
Examples of vestigial organs in plants: Scale like leaves on Indian pipe plant, Stamens which
lack anthers in some flowers.
[1]
v.
a.
b.
c.
vi.
a.
b.
[1]
[1]
[1]
Recycling is a type of green technology that uses old material to make new products. Many
waste products from the industries such as paper, glass, plastics and metals can be recycled.
[1]
Example: Old used tyres are recycled to create play ground flooring in parks to provide
soft surfaces that increase the safety of the children playing there.
[1]
Advantages of recycling:
[1]
1.
It conserves energy and raw materials.
2.
It saves space used in landfills.
3.
It protects environment by effective handling of waste materials.
4.
It reduces the cost of production.
[Any two points:½ mark each]
Sexual reproduction gives rise to variation.
[1]
Importance of variation in survival of species:
Variations give rise to variety and deversity. They enable organisms to adapt and survive
in the changing environmental conditions. Variations also help to prevent the complete
extinction of plant and animal species.
[2]
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Target Publications Pvt. Ltd.
8.
Board Answer Paper: March 2015
A.
i.
ii.
iii.
iv.
v.
Anaerobic reaction = 5
Reaction in human muscles = 4
Aerobic respiration = 3
Reaction in plant cells = 1
Reaction in liver = 2
[1]
[1]
[1]
[1]
[1]
B.
i.
ii.
The other two names of ethanol: Ethyl alcohol, Spirit.
The structural formula of ethanol:
H
H
[1]
H
C
C
H
H
OH
[1]
iii.
iv.
Properties of ethanol:
i.
It is a colourless liquid.
ii.
It is combustible and burns with a blue flame.
Action of phosphorus trichloride on ethanol:
When ethanol reacts with phosphorus trichloride (PCl3), it forms ethyl chloride and
phosphorus acid.
3C2H5OH + PCl3  3C2H5Cl + H3PO3
Ethanol
6
Phosphorus
trichloride
Ethyl
chloride
Phosphorus
acid
[1]
[2]