1.Young’s modulus of perfectly rigid body material is

a) Zero

b) Infinity

c) \[1\times 10^{10}N\diagup m^{2}\]

d) \[10\times 10^{10}N\diagup m^{2}\]

Explanation: Infinity

2. A wire of cross section \[4 mm^{2}\] is stretched by 0.1mm by a certain weight. How far (length) will be
wire of same material and length but of area \[8 mm^{2}\] stretch under the action of same force

a) 0.05 mm

b) 0.10 mm

c) 0.15 mm

d) 0.20 mm

Explanation:

3. A substance breaks down by a stress of 10^{6} N/m^{2}. If the density of the material of the wire is \[3\times 10^{3}kg\diagup m^{3}\] , then the length of the wire of the substance which will break under its own weight
when suspended vertically, is

a) 66.6 m

b) 60.0 m

c) 33.3 m

d) 30.0 m

Explanation:

4. A rubber cord 10 m long is suspended vertically. How much does it stretch under its own weight
(Density of rubber is \[1500 kg\diagup m^{3}\] , \[Y=5\times 10^{8}N\diagup m^{2}\] , \[g= 10m\diagup s^{2}\] )

a) \[15\times 10^{-4}m\]

b) \[7.5\times 10^{-4}m\]

c) \[12\times 10^{-4}m\]

d) \[25\times 10^{-4}m\]

Explanation:

5. The value of Poisson's ratio lies between

a) \[-1 to \frac{1}{2}\]

b) \[-\frac{3}{4} to -\frac{1}{2}\]

c) \[-\frac{1}{2} to 1\]

d) 1 to 2

Explanation:

6. The Poisson's ratio cannot have the value

a) 0.7

b) 0.2

c) 0.1

d) 0.5

Explanation: Value of Poisson’s ratio lie in range of -1 to \[\frac{1}{2}\]

7. 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

a) + 0.50

b) – 0.50

c) 0.25

d) - 0.25

Explanation:

8. A material has Poisson's ratio 0.50. If a uniform rod of it suffers a longitudinal strain of \[2\times 10^{-3}\] ,
then the percentage change in volume is

a) 0.6

b) 0.4

c) 0.2

d) Zero

Explanation:

Percentage change in volume = 4 * 10

^{-1}= 0.4%

9. Four identical rods are stretched by same force.
Maximum extension is produced in

a) \[L =10cm, D =1mm\]

b) \[L =100cm, D =2mm\]

c) \[L =200cm, D =3mm\]

d) \[L =300cm, D =4mm\]

Explanation:

10. The isothermal elasticity of a gas is equal to

a) Density

b) Volume

c) Pressure

d) Specific heat

Explanation: Isothermal elasticity K

_{i}= P