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Question

A cylindrical copper cable carries a current of 1160 A. There is a potential difference of 1.6 10-2 V between two points on the cable that are 0.39 m apart. What is the radius of the cable?

Answer 1

R=p L/A
V=IR
R=V/I= p L/A
from ref at 300K p=1.725e-8 ohms m

A= p L I /V

A= pi r^2

r= sqrt(p L I / (V pi) )
r=sqrt( 1.725e-8 x 0.39 x 1160 /( 1.6 e-2 x 3.14159))
r=0.0125 m
r=1.25 cm