Power

POWER

The rate of doing work or the rate of transfer of energy is called power. It is denoted by P Power = Work done / Time

P = W/ t

SI Unit: W (Watt) or J/s

1 kilowatt = 1000 watts

W = 1000 J s-1

Average Power = Total Energy Consumed / Total Time taken

Commercial Unit of Energy:

We cannot use Joule to measure power commercially. Instead, we use kilowatt-hour (kWh).

Commercial unit of energy = 1 kilowatt hour (kwh) 1 kWh = 1 kilowatt × 1 hour

= 1000 watt × 3600 seconds

 = 3600000 Joule (watt × second)

1 kWh = 3.6 × 106 J. 1 kWh = 1 unit

The energy used in one hour at the rate of 1 kW is called 1 kWh.