What is electric energy? What is its commercial (or practical) unit? Define it.

Explanation

"Electric energy is the amount of energy consumed in an electric circuit in a given time t."
The energy consumed not only depends upon the electric power of the appliance but also upon the time for which the power is maintained.
If a power P (watt) is maintained for time t (second), then the work done or electric energy consumed is

But the unit .watt. is very small. Therefore in actual practice we use a much larger unit called .kilowatt. which is equal to 1000 watt.
Since electrical energy is the product of power and time, the unit of electric energy is, therefore, watt hour (Wh).
"One watt hour is the energy consumed when 1 watt power is used for 1 hour."
The commercial (or practical) unit of electric energy is kilowatt hour (kWh), commonly known as .unit..
1 kWh = 1 kilowatt `xx` 1 hour
= 1000 watt `xx` 3600 second
`=3.6 xx 10^6` watt second
`=3.6 xx 10^6` joule (J)
Note: The unit kWh is equal to the electric I energy consumed, when electric power of 1 kW is consumed for 1 hour.
[If 10 electric bulbs, each of rating 100W are used for 1 hour, then 1 unit of electric energy is consumed.]