Question 388758
a) 14/60 kWh = 0.84 MJ

b) the heat capacity of water is 4180 J/kg/K, hence 1.5 l that is heated by 80 degrees needs an energy of : 4180*1.5*80 = 0.5016 MJ
 
hence the efficiency of the process is : (0.84 - 0.5016)/0.5016 = 67 %