Q 11-08-082JEE MainJEE Main 2021 (24 Feb, Shift 2)Easy
A uniform metallic wire is elongated by 0.04 m when subjected to a linear force $F$. The elongation, if its length and diameter is doubled and subjected to the same force will be ______ cm.
Numerical value type. Enter your answer.
Answer: 2
$\Delta l = \dfrac{FL}{AY} \propto \dfrac{L}{d^2}$. Doubling $L$ and $d$ multiplies $\Delta l$ by $\dfrac{2}{4} = \dfrac12$:
$$\Delta l' = 0.02\ \text{m} = 2\ \text{cm}$$
Solution by Sreeraj P, M.Sc Physics