Thermal Properties of Matter - Thermal Expansion Question with Solution | TestHub

A uniform metal rod fixed at its ends of $2{\mathrm{mm}}^2$ cross-section is cooled from $40^{\circ }\mathrm{C}$ to $20^{\circ }\mathrm{C}$. The coefficient of the linear expansion of the rod is $12\times 10^{-6}$ per degree and it's young modulus of elasticity is $10^{11}\mathrm{N}/{\mathrm{m}}^2$. The energy stored per unit volume of the rod is :