Question

A power transmission line is hung from metal towers with glass insulators having a resistance of 1.90 ✕ 10^9 Ω. What current (in mA) flows through the insulator if the voltage is 340 kV? (Some high-voltage lines are DC.)

Answer 1

From ohms law,

V = IR

I = V/R

where

V represents voltage

I represents current

R represents resistance

From the information given,

R = 1.90 ✕ 10^9

V = 340 kV

Converting 340 kV to volts, it becomes 340 x 10^3

Thus,

I = 340 x 10^3/1.90 ✕ 10^9 = 1.7895 x 10^-4 A

We would convert it to mA by dividing by 10^-3

Thus,

I = 1.7895 x 10^-4 /10^-3

I = 0.18 mA

The current that flows through the insulator is 0.18mA