When a.c. source is connected across a pure capacitor, the correct phase relation between current and emf is shown in figure.

Step-by-step solution

In an AC circuit containing a pure capacitor, the alternating current leads the alternating emf by a phase angle of 2 or 90^ . Mathematically, if the emf is given by e_c = E₀ ( t) , the current is given by I_c = I₀ ( t + 2 ) . In a phasor diagram, the phasor representing the current I_c must be rotated counterclockwise by 90^ relative to the phasor representing the emf e_c . Analyzing the given figures: (A) I_c and e_c are in phase (represents a pure resistor). (B) I_c leads e_c by 90^ (represents a pure capacitor)