A 1000 W heater is used for 6 hours. The electricity tariff is HK\$1.1 per kWh. What is the cost of using the heater?
Answer and explanation
Correct answer: A. HK\$6.6
- Step 1: Energy used kWh.
- Step 2: Cost dollars.
Answer
HK\$6.6.
Why not the others: HK\$6600: the power is not converted from W to kW. HK\$6: it gives the energy in kWh, not the cost. HK\$1.1: it divides by the time instead of multiplying.
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