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 ties, then 1
C) 1, 3, 2
D) 1, 2, 3
E) 3, 1, 2

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 ties, then 1 
C) 1, 3, 2 
D) 1, 2, 3 
E) 3, 1, 2

Quizplus · Accepted Answer

Circuit 1 has a large inductance, so the current takes longer to build up, resulting in a smaller initial current. Circuit 2 has no inductance, so the current can change instantaneously, resulting in a larger initial current. Circuit 3 has a small inductance, so the current takes less time to build up compared to Circuit 1, but more time compared to Circuit 2, resulting in an intermediate initial current. Therefore, the ranking of the initial current is 1 < 3 < 2.

The Diagrams Show Three Circuits with Identical Batteries, Identical Inductors