The correct expression for the instantaneous current if instantaneous

the-correct-expression-for-the-instantaneous-current-if-instantaneous

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).