Work done by restoring force in a wire within elastic limit is -10 J. Maximum amount of heat produced in the wire is

1. 10 J

2. 20 J

3. 5 J

4. 15 J

The work done per unit volume to stretch the length of area of cross-section 2 mm² by 2% will be
$\left[\mathrm{Y}=8\times {10}^{10} \mathrm{N}/{\mathrm{m}}^2\right]$

1. 40 MJ/m³ 

2. 16 MJ/m³ 

3. 64 MJ/m³ 

4. 32 MJ/m³ 

Which one of the following statements is wrong?

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.

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

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

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).