A wire of length L and radius r is  rigidly fixed at one end. On stretching the other end of the wire with a force F, the increase in its length is l. If another wire of same material but of length 2L and radius 2r is stretched with a force of 2F, the increase in its length will be

1. l                                       
2. 2l
3. $\frac{l}{2}$                                   
4. $\frac{l}{4}$ 

In steel, the Young's modulus and the strain at the breaking point are $2\times {10}^{11}N{m}^{-2}$ and 0.15 respectively. The stress at the breaking point for steel is therefore -

1. $1.33\times {10}^{11}N{m}^{-2}$           

2. $1.33\times {10}^{12}N{m}^{-2}$

3. $7.5\times {10}^{-13}N{m}^{-2}$           

4. $3\times {10}^{10}N{m}^{-2}$

Which one of the following substances possesses the highest elasticity:

1. Rubber                             

2. Glass

3. Steel                               

4. Copper

Which one of the following quantities does not have the unit of force per unit area?

1. Stress                                      

2. Strain

3. Young's modulus of elasticity

4. Pressure

A copper wire and a steel wire of the same diameter and length are connected end to end and a force is applied, which stretches their combined length by 1 cm. The two wires will have

1. Different stresses and strains

2. The same stress and strain

3. The same strain but different stresses

4. The same stress but different strains

The possible value of Poisson's ratio is

1. 1                                       

2. 0.9

3. 0.8                                     

4. 0.4

Which of the following affects the elasticity of a substance

1. Hammering and annealing

2. Change in temperature

3. Impurity in substance

4. All of these

A wire of diameter 1mm  breaks under a tension of 1000 N. Another wire, of the same material as that of the first one, but of diameter 2 mm, breaks under a tension of:

1. 500 N                               

2. 1000 N

3. 10000 N                           

4. 4000 N

There is no change in the volume of a wire due to change in its length on stretching. The Poisson's ratio of the material of the wire is

1. + 0.50                               

2.  – 0.50

3.  0.25                                  

4.  – 0.25

The force required to stretch a steel wire of cross-section $1 {\mathrm{cm}}^2$ to 1.1 times its length would be $\left(Y=2\times {10}^{11} N{m}^{-2}\right)$

1. $2\times {10}^{6}N$                               

2. $2\times {10}^{3}N$

3. $2\times {10}^{-6}N$                             

4. $2\times {10}^{-7}N$