Question

State two practical units of electric energy and define each.

Answer 1

1. Electrical energy is the energy derived from electric potential energy or kinetic energy of the charged particles.
2. The amount of electrical energy depends on the speed of the charge, the faster the charges move, the more electrical energy they carry.
3. SI unit of the electrical unit is $Joule\left(J\right)$.
4. Practical units of electric energy are watt-hour and kilowatt-hour.

(1). Watt-hour:

1. $1watt-hour=3600Joule$.
2. One watt-hour is the energy consumed when $1watt$power is used for $1hour$.
3. Watt-hour is used to measure electrical energy consumption.

(2). Kilowatt-hour:

1. The unit kWh is equal to the electric I energy consumed when the electric power of $1kW$ is consumed for $1hour$.
2. $1kilowatt-hour=3.6\times {10}^{6}Joule$.
3. The representation of the kilowatt-hour is “$kWh$”.