The modulus of elasticity of a material does not depend upon:

1. shape

2. temperature

3. nature of material

4. impurities mixed

What is the effect of temperature on the value of Young's modulus of elasticity for various substances, in general?

1. It increases with increase in temperature

2. Remains constant.

3. Decreases with rise in temperature

4. Sometimes increases and sometimes decreases with temperature.

The maximum load a wire can withstand without breaking, when its length is reduced to half of its original length, will:

1. be double

2. be half

3. be four times

4. remain same

The stress-strain graphs for two materials are: (assume same scale).

1. Material (ii) is more elastic than material (i) and hence, material (ii) is more brittle.

2. Material (i) and (ii) have the same elasticity and the same brittleness.

3. Material (i) is elastic over a larger region of strain as compared to (ii).

4. Material (ii) is more brittle than material (i).

A wire is suspended from the ceiling and stretched under the action of a weight F suspended from its other end. The force exerted by the ceiling on it is equal and opposite to the weight. Which of the following options is correct?

1. Tensile stress at any cross section A of the wire is F/A.

2. Tensile stress at any cross section is zero.

3. Tensile stress at any cross section A of the wire is 2F/A.

4. Tension at any cross section A of the wire is 2F.

Modulus of rigidity of ideal liquids is:

1. infinity

2. zero

3. unity

4. some finite small non-zero constant value

On abruptly withdrawing the stretching force acting on a wire, its temperature will:

1. increase

2. decrease

3. remain unchanged

4. nothing can be stated

On withdrawing the external applied force on bodies within the elastic limit, the body:

On stretching some substances, why is permanent elongation caused?

1. They are perfectly elastic.

2. They are perfectly plastic.

3. More stress acts on them.

4. Their strain is infinite.

Which one of the following statements is wrong?