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## Homework Statement

A cylindrical copper cable carries a current of 1300 A. There is a potential difference of 1.6 10-2 V between two points on the cable that are 0.38 m apart. What is the radius of the cable?

I=1300A

V=1.6e-2 V

l=0.38m

rho=1.7e-8(resistivity of copper)

r=?

## Homework Equations

V=IR

Where: V=voltage, I=Current, R=Resistance

R=rho* L/r^2pie

Where: R= resistance, rho=1.7e-8(resistivity of copper), Length in meters, r=radius

## The Attempt at a Solution

1. Find Resistance.

V=IR

1.6e-2V=1300A*R

R=1.23E-5 ohms

then I used:

R=rho* L/rpie^2

1.23E-5 ohms=1.7e-8*(0.38m/r^2pie)

2.09e-13=0.38m/r^2pie

6.57e-13=0.38m/r^2

6.57e-13*r^2=0.38m

5.78e11=r^2

r=760333.43m

what do I keep doing wrong??