Question

If S is stress and Y is Young’s modulus of material of a wire, the energy stored in the wire per unit volume is

• A. $\frac{S}{2y}$
• B. $\frac{2y}{S^2}$
• C. $\frac{S^2}{2y}$
• D. $2S^{2}Y$

Answer 1

The correct option is C $\frac{S^2}{2y}$

Energy stored per unit volume
$U=\frac{1}{2}stress\times strain$

$=\frac{1}{2}stress\times \frac{strain}{y}$

$=\frac{1}{2}S\times \frac{S}{y}$

$=\frac{S^2}{2y}$