9.4 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.

 

9a) The strain in rubber is more than that in steel for a given stress.

For the same stress: Y1Strain

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

(b) The ratio of the applied stress to the change in the shape of a body is known as the shear modulus.

The stretching of a coil changes its shape. Hence, shear modulus determines the elasticity of the coil in this process.