Two resistors of 10 W and 20 W and an ideal inductor of 10 H are connected to a 2 V battery
as shown. The key K is inserted at time t = 0. The initial (t = 0) and final (t →∞) currents
through battery are
The figure shows three circuits with identical batteries, inductors, and resistors. Rank the circuits according to the current through the battery (i) just after the switch is closed and (ii) a long time later, greatest first :
(i) Just after the switch is closed (t = 0): An inductor opposes any sudden change in current. Initially, it acts like an infinite resistance (open circuit). No current can flow through any branch containing the inductor at this instant.
(ii) A long time later (t =infinity): Once the current reaches a steady state, the inductor no longer opposes the flow. It acts like an ideal wire (short circuit) with zero resistance. You can then rank the circuits by calculating the total equivalent resistance of the remaining resistors.