Question

Complete the following sentences:
A Fuse wire is made of an alloy of _____ and _____.
A) Lead, tin
B) Nickel, lead
C) Cadmium, lead
D) Nickel, tin

Answer 1

A fuse is the electrical device that provides protection to the electrical circuits and prevents them from overloading and short circuits. Fuses are safety devices that are highly useful and necessary in any electrical system. In the absence of fuses, if too many appliances were operated on a single circuit, the current carrying conductor carrying the power for the circuit would highly heat up, cause short circuit, and possibly can also start a fire. For the prevention of such mishaps and electrical overloads, fuses are designed in such a way that they tend to trip or blow during any such electrical emergencies, hence ceasing the flow of current to the overloaded cable and avoiding further damages to the system.

Complete answer:
A fuse is a safety device in the field of electrical devices which is used in the circuit to protect electrical systems by breaking the connection during a short circuit. The fuse wire is composed of an alloy of two elements. It is made of $\mathrm{Sn}$ (tin) and $\mathrm{Pb}$ (lead) alloy due to the high resistance and low melting point of the resultant product. The tin and lead alloy is an eutectic composition which contains $62 \%$tin, and $38 \%$ lead, by composition. The resultant product melts at $183^{\circ} \mathrm{C}$.

Therefore, the correct answer is option A.

Note: The fuse must be directly connected to the mains at all times and it also must be of the correct value i.e., if a 15-ampere fuse trips during the current through it exceeding 15 amperes. A 20-ampere fuse blows during excess flow of current through it exceeding 20 amperes. Therefore, fuse wires are generally made of an alloy consisting of lead and tin because, should a current in a circuit exceed the said rating, the fuse wire will melt instantaneously.