Question

In a circuit inductance $L$ and capacitance $C$ are connected as shown in the figure. ${A_1}$ and ${A_2}$​ are meters. When the key $K$ is pressed to complete the circuit, then just after closing key ($K$), the readings of ${A_1}$​ and ${A_2}$ will be:

A) Zero in both ${A_1}$​ and ${A_2}$
B) Maximum in both ${A_1}$​ and ${A_2}$
C) Zero in ${A_1}$​ and maximum in ${A_2}$
D) Maximum in ${A_1}$​ and zero in ${A_2}$

Answer 1

Hint When an uncharged capacitor experiences a current, it will allow all the current to flow in it. When an uncharged inductor experiences a current, it will induce a voltage to oppose the external current due to Lenz law and won’t allow any current to flow.

Complete step by step answer
In the circuit given to us, when the switch is closed, the current will start to flow in the circuit. At the exact moment the switch is closed, there will be potential induced branches containing ${A_1}$​ and ${A_2}$.
Now, in the branch containing${A_2}$, there is an inductor. Since an uncharged inductor does not allow current to flow in the branch since it doesn’t want its magnetic flux to change. So there will be no current flow in the branch containing${A_2}$. So the reading of the ammeter ${A_2}$ will be zero
In the branch containing${A_1}$, there is an uncharged capacitor that will cause all current to flow across it when uncharged. So, the reading of the ammeter ${A_1}$ will be maximum when the switch is closed.
Since the reading of the ammeter ${A_2}$ is zero and the reading of the ammeter ${A_1}$ is maximum, the correct choice is option (D).

Note
The resistors that are present in the question are inconsequential for this question since they will determine the amount of current that flows in the circuit. But since we only want to determine whether the current in the ammeters will be maximum or zero, we only have to use the properties of inductors and capacitors.