The unit of electric energy is the watt hour (Wh). One watt hour is the energy consumed when 1 watt of power is used for 1 hour. The relationship between power, time, and electric energy is expressed by the formula: ...

The unit ‘watt’ is relatively small for practical usage, so a larger unit called ‘kilowatt’ is commonly employed. One kilowatt is equivalent to 1000 watts, making it more convenient to express power values in practical scenarios.

For an electric iron consuming 1 kW of electric power at 220 V, the current flowing in the circuit is (1000/220) A, which is approximately 4.54 A. In this case, a 5 A fuse must be used to ensure that ...

Fuses are rated with specific values to indicate the maximum current they can safely handle. These ratings (1 A, 2 A, 3 A, etc.) help in selecting an appropriate fuse for a specific circuit or device, ensuring protection without unnecessary ...

If a current larger than the specified value flows through the circuit, the temperature of the fuse wire increases. This rise in temperature causes the fuse wire to melt, breaking the circuit and preventing the flow of excessive current.