The adjacent graph shows the extension $\left(∆l\right)$ of a wire of length 1m suspended from the top of a roof at one end with a load W connected to the other end. If the cross sectional area of the wire is ${10}^{-6}{m}^2$ calculate the young’s modulus of the material of the wire

1. $2\times {10}^{11}N/m^2$

2. $2\times {10}^{-11}N/m^2$

3. $3\times {10}^{-12}N/m^2$

4. $2\times {10}^{-13}N/m^2$

The graph shows the behaviour of a length of wire in the region for which the substance obeys Hook’s law. $P$ and $Q$ represents:

             
1. $P$ = applied force, $Q$ = extension
2. $P$ = extension, $Q$ = applied force
3. $P$ = extension, $Q$ = stored elastic energy
4. $P$ = stored elastic energy, $Q$ = extension 

The diagram shows stress v/s strain curve for the materials A and B. From the curves we infer that

1. A is brittle but B is ductile  

2. A is ductile and B is brittle

3. Both A and B are ductile      

4. Both A and B are brittle

If the potential energy of a spring is V on stretching it by 2 cm, then its potential energy when it is stretched by 10 cm will be

1. V/25                                   

2. 5V

3. V/5                                    

4. 25V

Two wires of the same diameter of the same material having the length $l$ and $2l.$ If the force $F$ is applied on each, the ratio of the work done in the two wires will be:
1. $1 : 2$
2. $1 : 4$
3. $2 : 1$
4. $1 : 1$

A $5~\text{m}$ long wire is fixed to the ceiling. A weight of $10~\text{kg}$ is hung at the lower end and is $1~\text{m}$ above the floor. The wire was elongated by $1~\text{mm}.$ The energy stored in the wire due to stretching is:
1. zero                        
2. $0.05~\text J$ 
3. $100~\text J$                          
4. $500~\text J$

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. $Kl^2$

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