Question

Potential differences across resistor, inductor and capacitor are 60 V, 80 V and 20 V and all components in series. Then,

• A. Current leads voltage by ${45}^{\circ }$
• B. Voltage leads current by ${37}^{\circ }$
• C. Power factor is $\sqrt{2}$
• D. Voltage leads current by ${45}^{\circ }$

Answer 1

The correct option is D Voltage leads current by ${45}^{\circ }$

The voltage across resistor, capacitor, and inductor are proportional to their impedances. Hence, if the phasor diagram is drawn with impedances as multiples of their voltages, the figure below is obtained.

From the phasor diagram, it can be seen that the current will lag voltage by ${45}^{\circ }$.