Question

Which of the following is correct for fuse wire?
${\text{A}}{\text{.}}$ Low resistance and low melting point
${\text{B}}{\text{.}}$ High resistance and high melting point
${\text{C}}{\text{.}}$ High resistance and low melting point
${\text{D}}{\text{.}}$ Low resistance and high melting point

Answer 1

Hint- Here, we will proceed by discussing how exactly the fuse wire works when there occurs a short circuit or when a large amount of current is passed through the circuit. Then, we mentioned the characteristics needed for a wire to be fuse wire.

Complete step by step answer:
A fuse wire is a safety wire connected in series with the live wire, in case of any large current supply or malfunctioning in the electric connections it melts and breaks the electric circuit. A fuse wire is a piece of wire of a material with low melting point i.e., it melts and breaks as soon as its temperature gets higher than its melting point.
The material used for making the fuse wire should have low melting points and hence, the fuse wires are mainly made up of tin, lead or zinc.
The main objective behind using fuse wire in an electric circuit is to provide protection against short circuit or overload current. This means it protects the circuit from huge amounts of current flow as it causes damage to the circuit. The fuse wire is selected in such a way that it burns and breaks the circuit when large current passes. For this purpose, the material used as fuse wire should have high resistance and low melting point.
Due to high resistance the wire heats up quickly, when huge current flows. The temperature around the fuse wire rapidly rises, when it reaches the melting point of the material it burns and protects the circuits.
Therefore, the fuse wire will have high resistance and low melting point.
Hence, option C is correct.

Note- Apart from the required characteristics (i.e., low melting point and high resistance), the fuse wire should also be economical in practice. Although, silver satisfies both these required characteristics (i.e., low melting point and high resistance) but are not economical in nature, so it isn’t widely used as a material for fuse wire.