Q. Two wires of same diameter of the same material having the length $l$ and $2l$. If the force F is applied on each, the ratio of the work done in the two wires will be
A) 1 : 2
B) 1 : 4
C) 2 : 1
D) 1 : 1
Explanation
(a) $W = \frac{1}{2}\frac{(Stress)^{2}}{Y} \times Volume$
As $F,A$ and $Y$ are same $\Rightarrow W \propto$ Volume [area is same]
$W \propto l$ $(V = Al)$
$\frac{W_{1}}{W_{2}} = \frac{l_{1}}{l_{2}} = \frac{l}{2l} = \frac{1}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.