Q. A wire of length L, area of cross section A is hanging from a fixed support. The length of the wire changes to $L_1$ when mass M is suspended from its free end. The expression for Young's modulus is :
A) $\frac{Mg(L_1 - L)}{AL}$
B) $\frac{MgL}{AL_1}$
C) $\frac{MgL}{A(L_1 - L)}$
D) $\frac{MgL_1}{AL}$
Explanation
[Solution] $Y = \frac{F/A}{\Delta L/L} = \frac{MgL}{A(L_1 - L)}$. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.