When an alternating current given by I = 10sin (120π)t passes through a 12Ω resistor; the power dissipated in the resistor is?

A. 1200W
B. 600W
C. 120W
D. 30W

Correct Answer:

Option A – 1200W

Explanation

An a.c current is usually expressed as I = Io sin wt; and comparing this with the given current I = 10sin (120π)t, => Io = 10.
and power in an a.c circuit is given as:
P = I²R
= (10² x 12)
= 1200W