Question

A hot-water heater has an 8-ohm element that operates at 240 V. The power that's consumed by this water heater is A. 1,920 W. B. 30 W. C. 900 W. D. 7,200 W.

Answer 1

the information provided is

Voltage - 240 V , Resistance - 8 Ω and we are asked to find power

equation for power is

Power = voltage x current

P = VI

we know the voltage yet we dont know the current, we can find the current using the following equation

voltage = current x resistance

V = IR

substituting the values

240 V = I x 8 Ω

I = 30 A

Power = 240 V x 30 A

Power = 7200 W

answer is D. 7200 W