CTest+20E

  Which costs more--operating a 100 watt bulb for 12 hours, or a 2000 watt heater for half an hour?



 ANSWER: The light bulb costs more. (0.100 kW) x (12 h) = 1.2 kWh. (2.000 kW) x (0.5 h) = 1.0 kWh.