Question:
A compressive force, $F$ is applied at the two ends of a long thin steel rod. It is heated, simultaneously, such that its temperature increases by $\Delta \mathrm{T}$. The net change in its length is zero. Let $l$ be the length of the rod, $\mathrm{A}$ its area of cross-section, $Y$ its Young’s modulus, and $\alpha$ its coefficient of linear expansion. Then, $\mathrm{F}$ is equal to:
$l^{2} \mathrm{Y} \alpha \Delta \mathrm{T}$
$l \mathrm{AY} \alpha \Delta \mathrm{T}$
$\mathrm{AY} \alpha \Delta \mathrm{T}$
$\frac{\mathrm{AY}}{\alpha \Delta \mathrm{T}}$
Question of from chapter.
JEE Main Previous Year April 8, 2017
Correct Option: 3
Solution: