Author Question: You can choose between a heat pump and an electric heater to heat your house. If you assume that the ... (Read 41 times)

abern · **on:** Jul 28, 2018

You can choose between a heat pump and an electric heater to heat your house. If you assume that the electric heater is 100 efficient at turning electrical energy into heat, an electric heat pump of what coefficient of performance (COP) will result in the same cost of electricity for the same amount of heating? Assume that the motor that runs the heat pump is 100 efficient.
1.0.25
2.0.5
3.1.0
4.2.0

Question 2

If a car engine has a thermal efficiency of 50 and it does 500 J of work in one cycle, how much energy does it expel to the cold reservoir each cycle?

1.250 J.
2.500 J.
3.750 J.
4.1000 J.