A clothes dryer in a home has a power of 4,500 watts and runs on a special 220-volt household circuit,

1. what is the resistance of the dryer?

2. what is the current through the dryer?

3. how many kilowatt-hours of electricity are used by the dryer if it used for 4 hours in one week?

1). Power = (voltage) ² / (Resistance)

4,500 = (220) ² / Resistance

Multiply each side by (resistance) : 4,500 x resistance = (220) ²

Divide each side by 4,500 : Resistance = (220) ² / 4,500 = 10.76 ohms

2). Power = (voltage) x (Current)

Divide each side by (voltage) : Power / voltage = Current

4,500 / 220 = 20.45 Amperes

3). 4,500 watts = 4.5 kilowatts

(4.5 kilowatts) x (4 hours) = 18 kilowatt-hours