Question

Read the following two statements below carefully and state, with reasons, if it is true or false.

(a) The Young’s modulus of rubber is greater than that of steel;

(b) The stretching of a coil is determined by its shear modulus.

Answer 1

(a) False**(b)** True
For a given stress, the strain in rubber is more than it is in steel.

Young’s modulus, $Y =\frac{ Stress }{ Strain}$

For a constant stress: $Y ∝\frac{ 1 }{ Strain}$

Hence, Young’s modulus for rubber is less than it is for steel.

Shear modulus is the ratio of the applied stress to the change in the shape of a body. The stretching of a coil changes its shape. Hence, shear modulus of elasticity is involved in this process.