Q. A wire of Young’s modulus $1.5 \times 10^{12}\ Nm^{- 2}$ is stretched by a force so as to produce a strain of $2 \times 10^{4}.$ The energy stored per unit volume is
A) $3 \times 10^{8}\ Jm^{- 3}$
B) $3\ \times 10^{3}\ Jm^{- 3}$
C) $6\ \times 10^{3}\ Jm^{- 3}$
D) $3\ \times 10^{4}\ Jm^{- 3}$
Explanation
(d) Energy stored per unit volume
$= \frac{1}{2}Y\ (strain)^{2} = \frac{1}{2} \times 1.5\ \times 10^{12} \times \left( 2 \times 10^{- 4} \right)^{2}$
= $3\ \times 10^{4}\ Jm^{- 3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.