name the commercial unit of energy . establish a relationship b/w this unit and S.I unit of energy .
a battery lights a torch bulb .state the energy transformation envolved in this process
The commercial unit of electric energy is kWh.
1 kWh = 1000 W × 1 hour
= 1000 W × 3600 s
= 36 × 105 Ws
= 3.6 × 106 J
A battery lights a torch bulb, in this process chemical energy is converted into electrical energy.