Question

A steel rod of length 1 m is heated from ${25}^{\circ }C$ to ${75}^{\circ }C$ keeping its length constant. The longitudinal strain developed in the rod is (Given: Coefficient of linear expansion of steel $=12\times {10}^{-6}{/}^{\circ }C)n\times {10}^{-4}$ . Report n.

Answer 1

Strain developed:
$\in =\alpha \Delta T=(12\times {10}^{-6})\left(50\right)=6\times {10}^{-4}$
Strain will be negative, as the rod is in a compressed state.

Why this question? Key Concept: Strain without changing length- yes, that is possible by changing physical conditions. Caution: The length not changing does not imply 0 strain.