With rise in temperature, the Young's modulus of elasticity :

Solution

Physics sir · 4 steps

Heat loosens the grip between atoms, so the same stress now stretches the wire more.

1. What Y measures. Young's modulus is Y = stress/strain. It tells you how stiffly the interatomic bonds resist being pulled apart.
2. Effect of heating. On heating, atoms vibrate more and the average spacing between them grows. The restoring force between neighbours gets weaker, so the bonds give way more easily.
3. Same stress, more strain. For the same applied stress, the strain is now larger. A larger strain in the denominator means a smaller Y.
4. So. Young's modulus decreases steadily as temperature rises, which is option (c). For many metals the drop is small but steady.

The idea to keep. Elastic moduli come from the strength of interatomic forces. Anything that weakens those forces, like heating, lowers the modulus. Hotter materials are less stiff.

Answer from the NTA final answer key. Solution by PrepWiser.