Derive the relation between commercial unit of energy (kWh) and SI unit of energy (joule).
The relation between commercial unit of energy (kWh) and SI unit of energy (joule) is-
1kWh = 1000 W × 1h.
1 watt = 1 joule/1 sec
= 1000 × 60 × 60
= 3.6 × 106J