An electronic device has a power rating of 84 W when plugged

An electronic device has a power rating of 84. W when plugged into 110 V. Determine the resistance of the device. (A): 154 Ohm (B): 148. Ohm (C): 136.Ohm (D): 144.Ohm (E): 158.Ohm

Solution

We know that

P = V^2/R

R = resistance = ?

P = power = 84 W

V = Voltage = 110 V

So,

R = V^2/P

R = 110^2/84 = 144.04 ohm

Correct option is D.