Question

The resistance of a metal wire of length 1m is 26 ohm. If diameter of wire is 0.3mm what will be the resistivity of the metal at that temperature.

• A. 1.82 x ohm m
• B. 1.62 x ohm m
• C. 6.02 x ohm m
• D. 1.53 x ohm m

Answer 1

The correct option is A

1.82 x ohm m

R=$\frac{pl}{A}$ ; A= π $r^2$ = 3.14x$\frac{0.3}{2}$ x $\frac{0.3}{2}$ = 0.07 x ${10}^{-6}$
p=$\frac{RA}{I}$ = 26 x $\frac{0.07}{1}$ = 1.82 x ${10}^{-6}$ohm m