Question:
Given below are two statement : one is labelled as Assertion $A$ and the other is labelled as Reason R.
Assertion A : When a rod lying freely is heated, no thermal stress is developed in it.
Reason $R$ : On heating the length of the rod increases.
In the light of the above statements, choose the correct answer from the options given below:
Correct Option: 1
Solution:
$A$ and $R$ are true but $R$ is not the correc explanation of $\mathrm{A}$.