A 100 W bulb is switched on for 5 hours. How much electrical energy does it use?
Answer and explanation
Correct answer: C. 0.5 kWh
- Step 1: Energy in kWh is power in kW times time in hours. Step 2. kWh. Answer: 0.5 kWh. Why not the others: 5, 50 and 500 kWh come from using 1 kW, 10 kW or 100 kW instead of 0.1 kW.
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