Question

We have a heavy power cable which is 1 foot in diameter with resistance 0.05 u 12 per foot. Connect the cable to a voltage source of 115 V. How long is the cable over which the power loss through the resistance of the cable will reach 10^10 watts?

Answer 1

n = 26.5 ft

Step-by-step explanation:

given,

diameter = 1 ft

resistance, R = 0.05 μΩ/ft

Voltage, V = 115 V

Power, P = 10¹⁰ W

Length = ?

Power through the cable

P = I² R

P = (V/R)^2 x R

`P =(V^2)/(R)`

`R = (V^2)/(P)`

`R = (115^2)/(10^(10))`

R = 1.325 x 10⁻⁶ Ω

Length of cable in foots,

`R = n * R_(foot)`

`1.325* 10^(-6) = n* 0.05 * 10^(-6)`

n = 26.5 ft

Length of the cable is equal to n = 26.5 ft