Question

The resistivity of copper is 1.68 x 10^-8 W-m.  The resistance per unit length (R/L) of a certain copper cable is 1.61 x 10^-5W/m.

(a) What is the cross sectional area of the cable?

(b) The above cable is used to transmit electricity from a power station to an electrical substation 42.8 km distant.  If the voltage at the substation is 2480 V, what is the required voltage at the power station when the current running through the cable is 856 A?

(b) What is the total heat energy deposited (in Joules) in the wire in 1 hour?

Answer 1

A. Form the formula of the resistance we have a relationship as,

R = pL/A

Here p resistivity of copper =1.68× 10^-8 wm

L = length of the copper = 48.2km

A cross section area = to be find