Copper of fixed volume V is drawn into a wire of length l. When this wire is subjected to a constant force F, the extension produced in the wire is  Δl. Which of the following graphs is a straight line?

1. Δl versues 1/l
 

2. Δl versus l²
 

3. Δl versus 1/l²
 

4. Δl versus l

The Young's modulus of a rubber string 8 cm long and density $1.5 kg/m^3$ is $5\times {10}^8 N/m^2$, is suspended on the ceiling in a room. The increase in length due to its own weight will be

1. $9.6\times {10}^{-5} m$                           

2. $9.6\times {10}^{-11}m$

3. $9.6\times {10}^{-3} m$                           

4. 9.6 m

A and B are two wires of same material. The radius of A is twice that of B. They are stretched by the same load. Then the stress on B is

1. Equal to that on A

2. Four times that on A

3. Two times that on A               

4. Half that on A

If the length of a wire is reduced to half, then it can hold the ......... load

1. Half                                 

2. Same

3. Double                             

4. One fourth

Why the spring is made up of steel in comparison of copper?

1. Copper is more costly than steel

2. Copper is more elastic than steel

3. Steel is more elastic than copper

4. None of the above

Two wires of copper having length in the ratio of \(4:1\) and radii ratio of \(1:4\) are stretched by the same force. The ratio of longitudinal strain in the two will be:

The quality of the material which opposes the change in shape, volume or length is called

1.   Intermolecular repulsion

2.   Intermolecular behaviour

3.   Viscosity

4.   Elasticity

The possible value of Poisson's ratio is

1. 1                                       

2. 0.9

3. 0.8                                     

4. 0.4

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

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