Q. An elastic material of Young’s modulus Y is subjected to a stress S. The elastic energy stored per unit volume of the material is
A) $\frac{SY}{2}$
B) $\frac{S^{2}}{2Y}$
C) $\frac{S}{2Y}$
D) $\frac{2S}{Y}$
Explanation
(b) Energy per unit volume = $\frac{1}{2}\ \times stress \times strain$
$= \frac{1}{2} \times stress\ \times \frac{strain}{Y}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\ Y = \frac{stress}{strain} = \frac{S^{2}}{2Y}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.