Mechanical Properties of Solids

The Bulk modulus for an incompressible liquid is

• Zero

• Unity

• Infinity

• Between 0 to 1

Answer explanation

The bulk modulus for an incompressible liquid is considered to be infinity, as it does not change in volume when subjected to pressure.

The lower surface of a cube is fixed. On its upper surface, force is applied at an angle of 30° from its surface. The change will be in its

• Shape

• Size

• Volume

• Both shape and size

Answer explanation

When force is applied at an angle on the upper surface of a fixed cube, it will cause both a change in shape and size of the cube.

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

• 1/l²

• 1/l

• l²

• l

Correct pair is

• Change in shape – Longitudinal strain

• Change in volume – Shear strain

• Change in length – Bulk strain

• Reciprocal of Bulk modulus – Compressibility

The dimensions of two wires A and B are the same. But their materials are different. Their load- extension graphs are shown. If Y_A and Y_B are the values of Young’s modulus of elasticity of A and B respectively then

• Y_A > Y_B

• Y_A < Y_B

• Y_A = Y_B

• Y_B = 2Y_A

Two wires of the same length and material but different radii r₁ and r₂ are suspended from a rigid support both carry the same load at the lower end. The ratio of the stress developed in the second wire to that developed in the first wire is –

What is the percentage increase in length of a wire of diameter 2.5 mm, stretched by a force of 100 kg wt? Young’s modulus of elasticity of wire = 12.5 × 10¹¹ dyne/cm²

• 0.16%

• 0.32%

• 0.08%

• 0.12%

For steel, the breaking stress is 6 × 10⁶ N/m² and the density is 8 × 10³ kg/m³. The maximum length of steel wire, which can be suspended without breaking under its own weight is [g = 10 m/s²]

• 140 m

• 120 m

• 75 m

• 200 m

Poisson’s ratio cannot have the value:

• 0.1

• 0.7

• 0.2

• 0.5

One end of a uniform wire of length L and of weight W is attached rigidly to a point in the roof and a weight W₁ is suspended from its lower end. If s is the area of cross-section of the wire, the stress in the wire at a height (L/4) from its lower end is