The phase difference between virtual voltage and virtual current for a wattless current will be:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 90°
The average power in an ac circuit is \( P = V_{\mathrm{rms}}I_{\mathrm{rms}}\cos\phi \). A wattless current is one that flows without any power loss, so \( \cos\phi = 0 \).
\( \cos\phi = 0 \Rightarrow \phi = 90^\circ \)
NCERT (2026-27):
Power in AC Circuit: The Power Factor – “… Case (ii) Purely inductive or capacitive circuit: If the circuit contains only an inductor or capacitor, we know that the phase difference between voltage and current is \( \pi/2 \). Therefore, \( \cos\phi = 0 \), and no power is dissipated even though a current is flowing in the circuit. This current is sometimes referred to as wattless current.”