Q. Assertion (A) : With increase of temperature, elastic property of a substance decreases.
Reason (R) : Elasticity is due to intermolecular forces which decreases with the increase of intermolecular distance

 1944  213 Mechanical Properties of Solids Report Error

Solution:

On heating the mean position of atoms get disturbed and they changes their mean position ( the distance between them increases) this results in decrease of intermolecular forces among atoms and elastic property depends on intermolecular forces. Thus elastic property decreases.