• 2016: The answer is (A).

The charge on the capacitor increases exponentially with time. The time constant for the circuit is RC. So, the time taken for the charge to grow to (V/2) is RC ln 2.

  • 2017: The answer is (C).

The angular frequency of an LCR circuit is given by:

ω = 1 / √(LC)

If the capacitance is made 4 times, then the angular frequency will become:

ω = 1 / √(4LC) = 1 / 2 √(LC) = 1 / 2 ω

So, the angular frequency will become 1 / 4 times.