Question

A steel wire of length L and area of cross – section A shrinks by ∆l during night. Find the tension developed at night if Youngs modulus is Y and wire is clamped at both ends.

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

Answer 1

Answer: (D)

$\frac{AY\Delta l}{L}$

Answer 2

$\frac{\Delta l}{L} = \frac{F}{AY}orF = \frac{AY\Delta l}{L}$