Electromagnetic Induction And Alternating Current Ques 61

Answer:

Correct Answer: 61.(b)

Solution:

Formula:

Decay of current in the circuit containing resistor and inductor:

61. Initially in the given $R L$ circuit with a source, when $S_{1}$ is closed and $S_{2}$ is open at $t \leq t_{0}$.

$$ I_{1}=\frac{V}{R} \quad 1-\exp \frac{-R}{L} t $$

In this case, inductor $L$ is charging.

When switch $S_{2}$ is closed and $S_{1}$ is open (after $t>t_{0}$ ), the inductor will be discharged through resistor.

In this case $\left(t>t_{0}\right)$,

$$ I_{2}=\frac{V}{R} \exp -\frac{R}{L}\left(t-t_{0}\right) $$

Thus, the variation of $I$ with $t$ approximately is shown below