A)

Four incomplete statements are given below. Complete them by choosing the proper alternatives from those given and rewrite the completed statements in you answer book:

4

i)

A lens does not produce any deviation of a ray light passing through its ------.
a) Centre of curvature;   b) Optical centre;   c) Principal focus;
d) Axial point at a distance 2F from its centre.

ii)

The temperature at which air becomes saturated with water vapour is called -------.
a) Melting point      b) Boiling Point   
c) Dew Point          d) Freezing point.

iii)

The maximum size of the third row element is found in the atom of ------.
a) Sodium;    b) Chlorine;    c) Argon;    d) Aluminium.

iv)

The unit of electric current is called -------.
a) ampere;   b) volt;   c) ohm;   d) coulomb.

B)

Match the items in Column 'A' with their appropriate items in Column 'B' and write correct pairs in your answer book:

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1) 1 watt

a) 10⁶ watts

2) 1 horse-power

b) 10⁷ erg/second

3) 1 megawatt

c) 746 watts

d) 10⁷ erg

C)

Read the following sentences carefully and answer in the 'True' or 'False' form:

3

i)

If the concentration of a solution is approximately known, it is called a standard solution.

ii)

Biogas is produced by the fermentation of Biomass.

iii)

Energy and work have the same units.

A)

Give scientific reasons (any Three)

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1)

Rockets must have a very high driving power.

2)

Sound cannot be heard on the moon.

3)

Producer gas is used in the manufacture of Ammonia.

4)

X-rays are used for the detection of fracture of bones.

5)

The spring of a clock has to be wound again and again.

B)

Distinguish between any two of the following:

4

i)

Inert gas elements and Normal elements.

ii)

Anions and Cations.

iii)

Fossil fuel energy and solar energy.

A)

Solve the following examples (any Three)

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i)

A certain mass of water at 60°C is poured into an equal mass of water at 20°C. What will be the resulting temperature of the mixture?

ii)

Calculate the power of a concave lens of local length 40 cm.

iii)

A 250 gm ball is thrown vertically upward with a velocity of 10 m/s. Find the Potential Energy when it reaches maximum height.
(g = 9.8 m/s²)

iv)

Determine the P. D. which should be applied across a wire of resistance 50 ohms in order to send a current of 0.02 Ampere through it.

v)

49 gm of H₂SO₄ is dissolved in 10 litres of its solution. Find the normality of the solution. (H = 1, S = 32, O = 16)

B)

Write about any two safety precautions in the use of electricity at home.

4

A)

Draw neat and labelled diagrams (any Three of the following):

6

i)

Deflection of Cathode rays by an electric field;

ii)

Heating effect of electric current;

iii)

Formation of image by simple microscope;

iv)

Sound waves travelling through a liquid;

B)

State the new Cartesian sign convention with appropriate diagrams.

4

Explain the basis and working of an Atomic reactor.

A)

1)

Define: I) Inter-transition elements    ii) One Coulomb.

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2)

Write the law (any one):
I) Ohm's Law      ii) Modern Periodic Law

2

B)

Write any four properties of a - particles.

4

Q.6

A)

Give short answers of the following (ant three):

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i)

State any two uses of Biogas.

ii)

How is Potential Energy utilised to generate electrical energy in Hydro-electric power station?

iii)

What is meant by relative humidity?

iv)

"Velocity of light is greater than the velocity of sound." Explain the any two examples.

B)

i)

Anil's friend cannot see the blackboard writing but he can see nearby objects. What is his defect? Why is it caused? How is it corrected?

ii)

Anil's grandfather cannot see nearby objects clearly. What is his defect? Why is it caused? How is it corrected?