Question

A heater marked 2000W/3000W is switched on for 4 hours. For the first hour it is on the highest setting and for the last 3 hours it is on the lowest setting

1.1 How much energy does it transfer to the room in kWh (9kWh)
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Answer 1

9 kW-hr

Step-by-step explanation:

3000 W = 3 kW for 1 hr = 3 kW - hr

2000 W = 2 kW for 3 hr = 6 kW -hr

total power = 3 + 6 = 9 kW-hr