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. $2\times {10}^{-7}N$

A fixed volume of iron is drawn into a wire of length L. The extension x produced in this wire by a constant force F is proportional to:

1. $\frac{1}{L^2}$                                             

2. $\frac{1}{L}$

3. $L^2$                                               

4. L

The length of an elastic string is a metre when the longitudinal tension is 4 N and b metre when the longitudinal tension is 5 N. The length of the string in metre when the longitudinal tension is 9 N is

1. a - b                                             

2. 5b - 4a

3. 2b -$\frac{1}{4}\mathrm{a}$                                       

4. 4a - 3b

How much force is required to produce an increase of 0.2% in the length of a brass wire of diameter 0.6 mm ?

(Young’s modulus for brass = $0.9\times {10}^{11}N/m^2$)

1. Nearly 17 N                       
2  Nearly 34 N
3. Nearly 51 N                        
4. Nearly 68 N

A 5 m long aluminium wire $\left(Y=7\times {10}^{10}N/m^2\right)$ of diameter 3 mm supports a 40 kg mass. In order to have the same elongation in a copper wire $\left(Y=12\times {10}^{10}N/m^2\right)$ of the same length under the same weight, the diameter of the copper wire should be, in mm:

1. 1.75                                  
2. 1.5
3. 2.5                                   
4. 5.0