When strain is produced in a body within elastic limit, its internal energy:
1. Remains constant                  
2. Decreases
3. Increases                               
4. None of the above

When shearing force is applied to a body, then the elastic potential energy is stored in it. On removing the force, this energy:

1. converts into kinetic energy.

2. converts into heat energy.

3. remains as potential energy.

4. None of the above

A wire is suspended by one end. At the other end a weight equivalent to 20 N force is applied. If the increase in length is 1.0 mm, the increase in energy of the wire will be

1. 0.01 J                               
2. 0.02 J
3. 0.04 J                               
4. 1.00 J

The ratio of Young's modulus of the material of two wires is 2 : 3. If the same stress is applied on both, then the ratio of elastic energy per unit volume will be-

1. 3 : 2                                   

2. 2 : 3

3. 3 : 4                                   

4. 4 : 3

The stress versus strain graphs for wires of two materials A and B are as shown in the figure. If $Y_A$ and $Y_B$ are the Young ‘s modulii of the materials, then

1. $Y_B=2Y_A$

2. $Y_A=Y_B$

3. $Y_B=3Y_A$

4. $Y_A=3Y_B$

If a spring extends by x on loading, then the energy stored by the spring is (if T is tension in the spring and k is spring constant)

1. $\frac{T^2}{2x}$                                     

2. $\frac{T^2}{2k}$

3. $\frac{2x}{T^2}$                                     

4. $\frac{2T^2}{k}$

When a force is applied on a wire of uniform cross-sectional area $3\times {10}^{-6}{m}^2$ and length 4m, the increase in length is 1 mm. Energy stored in it will be $\left(Y=2\times {10}^{11}N/m^2\right)$

1. 6250 J                             
2. 0.177 J
3. 0.075 J                             
4. 0.150 J

A stretched rubber has:

1. increased kinetic energy.

2. increased potential energy.

3. decreased kinetic energy.

4. decreased potential energy.

When load of 5kg is hung on a wire then extension of 3m takes place, then work done will be

1. 75 joule                            

2. 60 joule

3. 50 joule                             

4. 100 joule

If the force constant of a wire is \(K\), the work done in increasing the length of the wire by \(l\) is:
1. \(\frac{Kl}{2}\)
2. \(Kl\)
3. \(\frac{Kl^2}{2}\)
4. \(Kl^2\)