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

     

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

If the force constant of a wire is K, the work done in increasing the length of the wire by l is:

1. $Kl/2$                                   

2. $Kl$

3. $K{l}^2/2$                                 

4. $K{l}^2$

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

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