Question

In the circuit shown below, all the inductors (assumed ideal) and resistors are identical. The current through the resistance on the right is $I$ after the key $K$ has been switched $ON$ for a long time. The currents through the three resistors (in order, from left to right) immediately after the key is switched $OFF$ are

• A. $2I$ upwards, $I$ downwards and $I$ downwards
• B. $2I$ downwards, $I$ downwards and $I$ downwards
• C. $I$ downwards, $I$ downwards and $I$ downwards
• D. $0,I$ downwards and $I$ downwards

Answer 1

Answer: (A)

In steady state, after the key remains $ON$ for a long time.

As resistances are identical and parallel (inductors behaves like closed paths), currents in resistors are equal as shown above. When switch is turned $OFF$, current in inductors remains same. So, we have following current distribution in circuit.

So, currents in resistances are $2I$ upwards, $I$ downwards and $I$ downwards