Question

In which of the following situations will a fuse possibly melt?
A. The earth wire is broken.
B. There is a short circuit in the electrical circuit.
C. The fuse is fixed along the neutral wire instead of the live wire.
D. The fuse wire is connected to earth wire.

Answer 1

Hint:A fuse is typically made up of a current-conducting strip or wire of easily fusible metal that melts and so interrupts the circuit of which it is a part whenever that circuit is designed to carry a current greater than that for which it is designed. Screw-plug fuses were historically widely employed in home electrical systems.

Complete answer:
When a fuse wire is exposed to the following conditions, it may melt:
(i) The earth wire is broken: surplus current that was supposed to be grounded via the earth wire no longer has a path to the earth. As a result, the excess current will melt the fuse wire instead.
(ii) The fuse is attached to the neutral wire rather than the live wire. Even if the fuse is anchored in the neutral line, it will melt. However, it will not perform its objective in terms of safety in that situation.
(iii) There is a short circuit in the electrical circuit: A short circuit causes a large current to flow, melting the fuse.

Hence, the correct options are:
(A) The earth wire is broken.
(B) There is a short circuit in the electrical circuit.
(C) The fuse is fixed along the neutral wire instead of the live wire.

Note: It should be noted that to provide stable and predictable features, the fuse element is constructed of zinc, copper, silver, aluminium, or alloys of these or other metals. In an ideal world, the fuse would carry its rated current eternally and melt fast in the event of a tiny excess. Minor harmless surges of current must not damage the element, and it must not oxidise or change its behaviour after years of operation.