Q 12-03-026NEETJEE MainTop questionEasy
A wire is stretched uniformly so that its length doubles. Its resistance becomes
Answer: (C) $4$ times
Volume is constant, so doubling $L$ halves $A$. $R = \dfrac{\rho L}{A}$ becomes $\dfrac{\rho(2L)}{A/2} = 4R$.
Solution by Sreeraj P, M.Sc Physics