Question

A uniform copper rod of length $50\text{cm}$ and diameter $3\text{mm}$ is kept on a frictionless horizontal surface at $20{}^{\circ }\text{C}$. The coefficient of linear expansion of copper is $2\times {10}^{-5}{}^{\circ }{\text{C}}^{-1}$ and Young's modulus is $1.2\times {10}^{11}{\text{N/m}}^2$. The copper rod is heated to $100{}^{\circ }\text{C}$, Then, the tension developed in the copper rod is

• A. $12\times {10}^3\text{N}$
• B. $36\times {10}^3\text{N}$
• C. $18\times {10}^3\text{N}$
• D. Zero

Answer 1

The correct option is D Zero

As the rod is not bounded at the ends, therefore there is no stress to counter the expansion. Hence, no tension in the rod.