The correct expression for the instantaneous current if instantaneous voltage is Vm(sint) in an inductive circuit is?
A. i = Vm(sint)/XL
B. i = Vm(cost)/XL
C. i = -Vm(sint)/XL
D. i = -Vm(cost)/XL
This question was addressed to me during an interview.
My question is from Alternating Current in a Resistive & Inductive Circuit topic in portion Single Phase Series Circuits of Basic Electrical Engineering
Right answer is D. i = -Vm(cost)/XL
Explanation: V=Vm*sint
I=V/XL = -Vm(cost)/XL (since current lags voltage by 900 in inductive circuit).