Question

A metal rod has length, cross-sectional area and Young's modulus as L, A and Y, respectively. If the elongation in the rod produced is l, then work done is proportional to ______.

Options

• l⁴

• l

• l³

• l²

Answer 1

A metal rod has length, cross-sectional area and Young's modulus as L, A and Y, respectively. If the elongation in the rod produced is l, then work done is proportional to l².

Explanation:

The work done in increasing the length of a metal rod is given by

W = `1/2 "AY"/"L" (Delta "L")^2`

Here, ΔL = I

∴ W ∝ l²