How much energy does it use during 20 min of operation?

Question

The resistance of an electric heater is 85 Ω when connected to 120 V. How much energy does it use during 20 min of operation?

Answer 1

Given

R = 85 Ω

V = 120 V

current, I = V/R

= 120V/85Ω

= 1.41 A

Power, P = VI

= (120V) (1.41A)

= 169.2 W

Energy = power x time

= (169.2 W) (20 * 60 s)

= 203 040 J

= 0.203 MJ