Question

A heater with an effective resistance of 4.8 ohms is connected to 240.0 volts if it operated approximately 25% of the time and electricity costs $0.10 per kWh what will be the electrical bill for30 days

Answer 1

-- Power used when the heater is running =

                         V²/R = (240)²/4.8= 12,000 watts. (12 KW)

(A gigantic heater ... suitable for maybe a theater, not for a home.)

-- Energy consumed in one day:

                 (12 KW) x (24 hours) x (25%) = 72 KwH per day

-- Energy consumed in 30 days:  (72 KwH/day) x (30 days) =

                  2,160 KwH in 30 days

-- Cost = ($0.1 / KwH) x (2,160 KwH) = $216.00  in 30 days