**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:**