Question

Resistance of a metal wire length 2m is 40 Ohm. if diameter of the wire is 2mm. what will be the resistivity of the metal.

Answer 1

R=(rho*l)/A

rho=(R*A)/l

R=resistance (40 ohms)
rho=resistivity (To find)
l=length of wire(2 m)
A= cross sectional area of wire

d,diameter of wire is given as 2*10^-3 m

radius of wire equals 10^-3 m

A equals pi*r^2

find A and substitute the given data in second formula