Question

SI unit of electrical energy is
A) Joule
B) Kilowatt-hour
C) KiloJoule
D) Watt-hour

Answer 1

Hint : Electricity is a phenomenon in itself involving the movement of electrons. Electric power is defined as the electric energy consumed in a unit amount of time.

Complete step by step answer
Electrical energy is supplied by the combination of electric current and electric potential that is driven in an electrical circuit. All electrical energy is a form of potential energy that arises from a potential difference between two points unless it is converted to another type of energy.
Kilowatt-hour is also a unit of energy as it is the product of power in the circuit with the time duration. However, it is not the SI unit of electrical energy.
A kilojoule is also a unit of energy but it is also not the SI unit of electrical energy.
Watt-hour is also a unit of electrical energy but again it is not the SI unit.
The typical unit of electrical energy is the joule or watt-second. However, the SI unit of electrical energy is the same as any other form of energy which is Joules.
Hence the correct choice is option (A).

Note
It is possible to confuse electrical power and electrical energy. Electrical power has the SI units of Watt while electrical energy has the SI units of Joule. The rate of energy transferred per unit time gives us the electrical power transferred in the circuit. The SI unit of electrical energy is the same as the SI units of energy in any other system which is Joules.