Q. What among of work is done in increasing the length of a wire though unity ?
A) $\frac{YL}{2A}$
B) $\frac{YL^{2}}{2A}$
C) $\frac{YA}{2L}$
D) $\frac{YL}{A}\ $
Explanation
(c) Work done = $\frac{1}{2}F\ \times \ $extension
$\ \ \binom{= \ \frac{1}{2}\ \times \ \frac{YA}{L}\ \times \ 1}{= \ \ \frac{YA}{2L}\ }\ \ \left| \begin{array}{r}
Y = \frac{F \times L}{A \times 1} \\
F = \frac{YA}{L}
\end{array} \right.\ $
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.