Răspuns:
1J = 1W×1s
1kWh = 1000W×3600s = 3600000 J
1 kWh .................. 3600000 J
6.5 kWh .............................x J
x = 3600000*6.5/1 = 23400000 J
1 kWh .................. 3600000 J
x kWh ...................1080000 J
x = 1*1080000/3600000 = 0.3 kWh