Question

The resistance of a wire is $1\Omega$. It is so stretched that the length become 10 times , then the new resistance of the wire will be:

• A. $25\Omega$
• B. $10\Omega$
• C. $100\Omega$
• D. $1/2\Omega$

Answer 1

Answer: (C)

$100\Omega$

Resistance of the wire $R=\frac{\rho L^2}{V}$ where $\rho$ and $V$ are constants

$⟹$ $R\propto L^2$

$\therefore$ $L^{\prime }=10L$ $⟹R^{\prime }=100R=100\times 1=100\Omega$