Write the function of a fuse.

Hint: As a first step, you could think what a fuse actually is. You could then mention why a fuse is considered one of those devices that is a must presence in an electric circuit. You could also explain what happens in the absence of it. You could also mention all the terms related to it and also give where it is connected.

Complete answer:
In the question, we are asked about the function of a fuse.
Basically, a fuse is an electrical safety device that provides protection to an electrical circuit when there is over-current flow. The basic structure of a fuse consists of a metal wire that has an ability to melt down when excess current flows through it thus stopping the flow of excess current.
Another term that you should be aware of is the fuse rating of a fuse. It can be defined as the amount of current that is required to break the fuse, that is, the maximum current that can pass through a fuse that would cause the fuse to blow off.
The fuses are connected to live wires as they are the ones that are connected directly to the generators of the electric supply company. By connecting the fuse wire to these live wires, cuts this direct connection when the fuse melts itself and thereby preventing the appliance from damage due to the excess current flow.

Note:
A fuse is often called a self sacrificial device. This is because it blows off when there is too much current in the circuit and protects the circuit by sacrificing itself. But, when this happens it should be replaced sooner than later, for the circuit is vulnerable in the absence of a fuse in it. Fuses come into operation in the case of short circuits, overloading, mismatched loads or device failure.