If an electric heater uses 3 kW when on, how much energy does it use in 4 hours?

Study for the IGCSE Physics Electricity Test. Master key concepts with flashcards and multiple choice questions, each providing hints and explanations. Prepare with confidence for your exam!

Multiple Choice

If an electric heater uses 3 kW when on, how much energy does it use in 4 hours?

Explanation:
Energy used equals power times time. At 3 kW for 4 hours, the energy is 3 × 4 = 12 kWh. So the heater uses 12 kilowatt-hours of energy. As a check, 3 kW is 3000 W and 4 hours is 14,400 seconds. P × t = 3000 × 14,400 = 43,200,000 J, which is 12 kWh because 1 kWh = 3.6 × 10^6 J.

Energy used equals power times time. At 3 kW for 4 hours, the energy is 3 × 4 = 12 kWh. So the heater uses 12 kilowatt-hours of energy.

As a check, 3 kW is 3000 W and 4 hours is 14,400 seconds. P × t = 3000 × 14,400 = 43,200,000 J, which is 12 kWh because 1 kWh = 3.6 × 10^6 J.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy