A power transmission line is hung from metal towers with glass insulators having a resistance of 1.00 times 10^9 ohms. What current flows through the insulator if the voltage is 200 kV? (Some high-voltage lines are DC.)

The current through the insulator can be calculated using Ohm's law: {eq}I = \frac{V}{R} {/eq} where: I = current V = voltage R = resistance Substituting the given values, we get: {eq}I = \frac{200 mathrm{kV}}{1.00times10^9 Omega} = 0.2 mathrm{A} {/eq} Therefore, the current through the insulator is 0.2 amperes. This is a very small current, which is expected as insulators are designed to prevent electrical current from flowing through them. The large resistance of the glass insulators ensures that only negligible amounts of current can flow, while allowing the high voltage to be transmitted along the power line.