Q 11-08-011NEETJEE MainTop questionMedium
A steel rod is held tightly between two rigid walls and heated through $50^\circ$C. For steel, $\alpha = 1.2 \times 10^{-5}\ \text{K}^{-1}$ and $Y = 2 \times 10^{11}$ N m$^{-2}$. The stress developed in the rod is
Answer: (C) $1.2 \times 10^8$ N m$^{-2}$
The rod would expand by strain $\alpha\Delta T$, but the walls prevent it, so the same strain appears as compression.
Stress $= Y\alpha\Delta T = 2 \times 10^{11} \times 1.2 \times 10^{-5} \times 50 = 1.2 \times 10^8$ N m$^{-2}$. It does not depend on the rod's length or area.
Solution by Sreeraj P, M.Sc Physics