Question

A fixed volume of iron is drawn into a wire of length L. The extension x produced in this wire by a constant force F is proportional to

• A. $\frac{1}{L^{2}}$
• B. $\frac{1}{L}$
• C. $L^{2}$
• D. L

Answer 1

Answer: (C)

$L^{2}$

Answer 2

$l = \frac{FL}{AY} = \frac{FL^{2}}{ALY} = \frac{FL^{2}}{VY}$ for a fixed volume $l \propto L^{2}$