Question

Match the terms/statements in column A with those in column B.

Column 1	Column 2
live wire	kW
electrical power	brown
neutral wire	yellow
electrical energy	blue
earth wire	kWh

Answer 1

Neutral wire 1 live wire - brown

• A live wire is a wire carrying an electric current
• The live wire of each circuit passes through a separate fuse (or circuit breaker).
• Separate fuses (or circuit breakers) for each circuit are provided so that if short-circuiting or overloading of any circuit takes place then, only the fuse of that particular circuit will blow-off, while rest of the circuits remain unaffected

2 electrical power -kW

One joule is the amount of energy consumed when an electrical appliance of one watt rating is used for one second.

$$\begin{gathered} electricalpower=workdone/time \\ p=w/t \\ watt=joule/second \\ killowatt={10}^{3}watt=1000watt \end{gathered}$$

hence electrical power = kW

3 Neutral wire - blue

• Sometimes, the live and the neutral wires in a circuit touch each other due to defective or damaged wiring.
• Because of this, the resistance of the circuit becomes almost zero, and very large current flows through it.

4 Electrical energy - kWh

• Commercial unit of electrical energy. The SI unit of electrical energy is joule.
• One joule represents very small amount of energy.
• So, for commercial purposes, a bigger unit called kilowatt-hour is used.

The commercial unit of electrical energy is kilowatt-hour (kWh)

5 Earth wire - brown

One of the three wires coming from the main supply line is called earth wire.

The other end of the earth wire (near the electric pole) is connected to a large metal plate buried deep (about 5 metre) inside the earth

Connecting the metallic body of an electrical appliance to the earth by a conducting wire is called the earthing of an appliance.