Q 11-08-024JEE MainJEE Main 2026 (5 Apr, Shift 2)Easy
A copper wire of length $3$ m is stretched by $3$ mm by applying an external force. The volume of the wire is $600 \times 10^{-6}\ \text{m}^3$. The elastic potential energy stored in the wire in stretched condition would be ______ J. (Given Young modulus of copper $= 1.1 \times 10^{11}\ \text{N/m}^2$)
Numerical value type. Enter your answer.
Answer: 33
Concept. Energy stored in a stretched wire is $\tfrac12\times\text{stress}\times\text{strain}\times\text{volume}=\tfrac12Y(\text{strain})^2V$.
Step 1. Strain. $\dfrac{3\times10^{-3}}{3}=10^{-3}$.
Step 2. Energy.
$$U=\frac12\times1.1\times10^{11}\times(10^{-3})^2\times600\times10^{-6}=\frac12\times1.1\times10^{11}\times6\times10^{-10}=33\ \text{J}$$
Answer. $33$.
Solution by Sreeraj P, M.Sc Physics
