Question

A uniform wire of length $l$ and radius $r$ has a resistance of $100\Omega$. It is recast into a wire of radius $\frac{r}{2}$. The resistance of new wire will be

• A. $1600\Omega$
• B. $400\Omega$
• C. $200\Omega$
• D. $100\Omega$

Answer 1

Answer: (A)

$R\propto \frac{1}{r^4}$