Question

What is the SI unit of electrical energy consumed?

Answer 1

Step 1. Electrical energy

1. Electrical energy is defined as the energy generated by the movement of electrons from one point to another across the conductor.
2. The dimensional formula for electric energy is $[{\mathrm{M}}^1{\mathrm{L}}^2{\mathrm{T}}^{-2}]$.
3. The mathematical expression of electric energy is, $\mathrm{E}=\mathrm{QV}$, where $\mathrm{E}$ represents the electric energy, $\mathrm{Q}$ is the charge, and, $\mathrm{V}$ is the potential difference.

An illustrative diagram of the electric energy consumed by various appliances is given below.

Step 2: SI unit of electrical energy

1. The SI unit of electrical energy consumed is joules and is represented by $\mathrm{J}$.
2. It is also measured in $\mathrm{kWh}$.
3. When $1\mathrm{kW}$ of power is consumed by an electric appliance in 1 hour, then the electrical energy consumed by the appliance is said to be $1\mathrm{kWh}$.
4. $1\mathrm{kWh}=3.6\times {10}^6\mathrm{Joule}$.