Electrical Engineering - Capacitors - Discussion

The capacitor does not allow sudden changes in voltage, therefore, the voltage across the capacitor is zero. Similarly, Inductor does not allow sudden changes in current.

Initially, as given in the problem the capacitor is in uncharged condition.at the instant when the switch is closed the voltage across the capacitor is zero because the capacitor only charges when an infinite amount of current flows through it. So, at the time of starting not much amount of current flows through ckt and hence, the voltage across the capacitor is 0
We know;

C = Q/V.
V = Q/C.

And also Q=idt at the starting there is no change in current with respect to time due to that there is no change accumulation.

For DC source, capacitor act like open.

Here it's using DC source (battery) so the circuit will act like open.

Q=CV,
V=Q/C,
Because capacitor is uncherged soQ=0 c.
So V=Q/C= 0/C =0V.

Is capacitor works under DC?

The capacitor rating is independent of voltage hence it's zero.

C does not allow the sudden change in voltage so here at t = (0-) C have no charge it is given in question then at t = (0+) C behave like a short circuit and we know that short circuit have 0 voltage.

Actually voltage across capacitor can not change instantaneously so in this change case answer is zero.

For DC source its act as open.