In an electrical circuit, the current passing through a conductor varies inversely with the resistance. Suppose that when the current is 17 A (amperes), the resistance is 10 ohms. What is the resistance when the current is 5a?

1 Answer
Apr 10, 2016


34 ohms


In physics this is Ohm's Law, where voltage = current x resistance. Thus, an electrical circuit would be V = 17 x 10, or V = 170 volts. Now, in a real circuit, if the voltage remains constant and the current changes, the resistance will change proportionally. In this case it would be 170 = R x 5, or R = 170/5 = 34 ohms. In the same way, adding resistance to a circuit with a fixed voltage reduces the current through the circuit.

In the case of a simple stated inverse proportional relationship we can simply write the current ratio as 17/5. Then the corresponding changed resistance ratio would be 10/R. The INVERSE is R/10 so the equation is 17/5 = R/10 ; R = 10(17/5) ; R = 170/5 ; R = 34