A 1000 W heater is used for 6 hours. The electricity tariff is HK\$1.5 per kWh. What is the cost of using the heater?
Answer and explanation
Correct answer: A. HK\$9
- Step 1: Energy used kWh.
- Step 2: Cost dollars.
Answer
HK\$9.
Why not the others: HK\$9000: the power is not converted from W to kW. HK\$6: it gives the energy in kWh, not the cost. HK\$1.5: it divides by the time instead of multiplying.
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