Question

A steel wire of length $L$ and area of cross-section A shrinks by $\Delta l$ during night. Find the tension developed at night if Young's modulus is $Y$ and wire is clamped at both ends

• A. $\frac{AYL}{\Delta l}$
• B. $AYL$
• C. $AY\Delta l$
• D. $\frac{AY\Delta l}{L}$

Answer 1

The correct option is D $\frac{AY\Delta l}{L}$

$\frac{\Delta l}{L}=\frac{F}{AY}orF=\frac{AY\Delta l}{L}$ (using standard equation)