COMEDK2023Morning ShiftPhysicsAlternating CurrentActual
In the case of an inductor
Options
- Avoltage lags the current by / 2
- Bvoltage leads the current by / 3
- Cvoltage leads the current by / 2
- Dvoltage leads the current by / 4
Correct answer
C. voltage leads the current by / 2
Step-by-step solution
In an ideal inductor, the voltage V across the inductor is related to the current I by the equation V = L dI dt . Let the current be I = I₀ ( t) . Then the voltage is V = L d dt (I₀ ( t)) = L I₀ ( t) . Using the trigonometric identity ( t) = ( t + / 2) , we get V = V₀ ( t + / 2) , where V₀ = I₀ L . Comparing the phases of current and voltage, the voltage leads the current by a phase angle of / 2 . Answer: voltage leads the current by / 2