Question

When an AC source is connected across a pure capacitor, the correct phase relation between current (i_c) and voltage (e_c) is shown in the figure.

(A)	(B)	(C)	(D)

Options

• (A)

• (D)

• (B)

• (C)

Answer 1

(B)

Explanation:

The voltage across a pure capacitor in an AC circuit is given by,

e_c = e₀ sinωt ..............(i)

and current across it is given by,

`i_c = i_0 sin(omegat + pi/2)` ...........(ii)

From Eqs. (i) and (ii), we observe that the current in the capacitor is leading the voltage by `pi/2`. So, the correct phase of the diagram is shown in Figure B.