Question

lenght of a wire is 314 cm radius is 1mm .find the resistivity of wire if resistance is 0.02 ohm=(2×10-8ohm m)

Answer 1

Given,
L=314cm
=>L=314/100 m
=>L=3.14m
r=1mm
=>r=1/1000m
=>r=10^-3m
R=0.02Ohm
We know,
R=(Rho)×L/A
=>(Rho)=R×A/L
=>(Rho)=R×(πr²)/3.14
=>(Rho)=0.02×3.14×(10^-3)²/3.14
=>(Rho)=0.02×10^-6Ohm meter
=>(Rho)=2×10^-8Ohm meter.
[Here π=3.14, because of simplicity purposes.]