Q. The work per unit volume to stretch the length by 1% of a wire with cross sectional area of $1mm^{2}$ will be $\lbrack Y = 9 \times 10^{11}N/m^{2}\rbrack$
A) $9 \times 10^{11}J$
B) $4.5 \times 10^{7}J$
C) $9 \times 10^{7}J$
D) $4.5 \times 10^{11}J$
Explanation
(b) $U = \frac{1}{2} \times Y \times (Strain)^{2} = \frac{1}{2} \times 9 \times 10^{11} \times \left( \frac{1}{100} \right)^{2}$
$= 4.5 \times 10^{7}J$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.