Question

A 1.06-mF capacitor is connected to a North American electrical outlet (ΔVrms = 120 V, f = 60.0 Hz). Assuming the energy stored in the capacitor is zero at t = 0, determine the magnitude of the current in the wires at t = 1/173 s.

A

Answer 1

V=Vo sin(wt) where Vo=√2Vrms

As given initially energy is zero , that's why we must take sin(wt) not cos(wt) as on taking cos(wt) ,initial energy would not be Zero.

Then differentiating voltage with respect to time and multiplying by capacitance gives us current.