The diagrams show three circuits with identical batteries, identical inductors, and identical resistors.Rank them according to the current through the battery just after the switch is closed, from least to greatest.
A)3, 2, 1
B)2 and 3 tie, then 1
C)1, 3, 2
D)1, 2, 3
E)2, 3, 1

Question

The diagrams show three circuits with identical batteries, identical inductors, and identical resistors.Rank them according to the current through the battery just after the switch is closed, from least to greatest. 
A)3, 2, 1 
B)2 and 3 tie, then 1 
C)1, 3, 2 
D)1, 2, 3 
E)2, 3, 1

Quizplus · Accepted Answer

In circuit 1, the inductor has no effect as it is shorted by the switch, so the initial current through the battery is simply determined by the resistance of the circuit. In circuit 2, as the switch is closed, the inductor opposes changes in current, and initially behaves as if it were a resistor. This means that the total resistance of the circuit, and therefore the initial current, is greater than in circuit 1. In circuit 3, the inductor initially behaves like a short circuit, effectively bypassing the resistor, so the total resistance of the circuit and therefore the initial current is the lowest of the three.

The Diagrams Show Three Circuits with Identical Batteries, Identical Inductors