Question

Figure shows the circuit that contains three resistances (\(9\,\Omega\) each) and two inductors (\(4\,\text{mH}\) each). The reading of ammeter at the moment switch \(K\) is turned ON, is _________ A.

• A. zero
• B. \(2\)
• C. \(3\)
• D. \(1\)

Hint:

An inductor behaves like an open circuit at the instant a DC supply is switched ON.

Answer 1

The Correct Option is A

Step 1: Behaviour of inductors at the instant of switching.
At the moment the switch is turned ON (\(t=0\)), inductors oppose any sudden change in current and behave like open circuits.

Step 2: Analyze the circuit at \(t=0\).
Since both inductors act as open circuits initially, all branches containing inductors are effectively broken. As a result, there is no closed conducting path for current through the ammeter.

Step 3: Ammeter reading.
Because no current flows at the instant of switching ON, \[ I = 0. \]

Final Answer: \[ \boxed{0} \]