How much energy in kWh does a 500 W heater use in 4 hours?
Answer and explanation
Correct answer: A. 2 kWh
- Step 1: Energy (kWh) = power (kW) × time (h). Step 2. 500 W = 0.5 kW, so E = 0.5 × 4 = 2 kWh. Answer: 2 kWh. Why not the others: 2000 kWh is what you get if you forget to convert watts to kilowatts. 0.125 kWh is what you get if you divide by the time. 20 kWh is what you get if you divide by 100 instead of 1000.
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