What is commercial unit of energy?

CBSE Class 9 CBSE Class 9 Science
,
1

(i) What is commercial unit of energy? Give its relation with SI unit of energy.
(ii) An electrical oven is rated 2500 W. How many units of energy does it consume in 4 h?

2

(i) Commercial unit of energy is kilowatt hour (kWh).
The SI unit of energy is joule.
1 kWh = 3.6x ${{10}^{6}}$J
(ii) Given, P = 2500 W, t = 4 h
E = P/T = 2500/ 1000 x 4 = 10 kwH = 10 units.