The Student Room Group
Reply 1
anybodyyyy...?
Reply 2
current is the rate of flow of charge i.e. dQ/dt

We know that Q=CV

therefore

dQ/dt = C . dV/dt

therefore I = C. dV/dt

and we have an expression for V in terms of t.

do you see what you have to do?
Reply 3
dont forget that there are two capacitors in parallel, so take that into account before you do the above for them.
Reply 4
so for one, if I = C. dV/dt, its C. Vcos (omega t) ?

i'm really not getting this :s-smilie:
Reply 5
and is it that

It = CV?
Reply 6
wgeipfm
and is it that

It = CV?


yes, that is correct.
Reply 7
That's wrong ...the differential is omegaVcos(omega t). The V in this expression is the peak voltage. The current is therefore C.omega.Vcos(omega t). This is the full expression for the current in each capacitor, as you have stated the question, where V is the peak voltage. Don't sub CV for I as you introduce another unknown into the answer (I, the peak current).

Latest