1.600w * 1h = 0.6kwh,0.6度电
2.U^2/R = P ,所以U^2/P = R = 220*220/600 = 80.67欧
3.20min是1/3小时,也就是耗电0.2kwh,如果不考虑效率,耗的电全部转化为热,0.2kwh相当于0.2*3.6*10^6J = 720千焦