Question

Resistance of a metal wire of 1m length is 20 ohm. If the diameter of wire is 5mm.What will be the resistivity?

Answer 1

R=бl/A

where

R=resistance

l=lenght

A=area

б=resistivity

20=б1/πr²

r=2.5*10⁻³

б=20*3.14*(2.5*10⁻³)²/1

=392.5*10⁻⁶

=3.92*10⁻⁴