CHEMICAL EFFECTS OF ELECTRIC CURRENT
The electric energy consumed by an electrical appliance is given by the product of its power and the time for which it is used i.e.
Electrical energy = Power X time
or, E = P X t
The S.I. unit of electrical energy is 1 joule
One joule is the amount of electrical energy consumed when an electrical appliance of 1 watt power is used for one second, i.e.
1 Joule = 1 watt X 1 second
or 1 J = 1 w X 1 s
or 1 J = 1ws
Commercial Unit of Energy: - Kilowatt Hour
One kilowatt hour is the total electrical energy consumed when an electrical appliance having a power of 1 Kilowatt is used for 1 hour. It is written as kWh in short form.
Relationship between Kilowatt Hour and joule
1 kWh = 1 kilowatt X 1 hour
so 1 kWh = (1000w) X (60 X 60 sec.)
= 3600000 watt seconds
or 1 kWh = 3.6 X 106 J
Test Your Understanding and Answer These Questions:
- What is electric energy?
- What is 1 joule?
- What is commercial unit of energy?
- Define 1 kilowatt hour.
- What is the relationship between kilowatt hour and joule?