Question

What is immaterial for an electric fuse?
A. Its length.
B. Its radius.
C. Its specific resistance.
D. current flowing through it.

Answer 1

Hint: We can also say that the rate of heat loss from the wire in a part can be determined by its surface area. When we double the length, we double the ability of the piece of metal to radiate away the heat that is being generated. So we generate twice as much heat, but it radiates away twice as fast compared to a single-length piece. So we can see that the temperature of a 2x long wire is the same as a 1x long wire, which means that the fusing/melting current is the same independent of length.

Complete step by step answer:
We will see if high current is passed through the fuse wire then the wire burns and disconnects the power supply the thickness of fuse determines how much current can be passed hence fuse of any length can be used but it's thickness should be proper. The length of electric fuse wire is immaterial because it is used to avoid danger due to high current.
 Therefore the immaterial for fuse is length.
Hence the correct option is A.

Additional information:
The most suitable materials for fuse wire is made of zinc, copper, silver, aluminium, or alloys to provide stable and predictable characteristics. Fuse should be of low resistance and low melting point because of the requirement current rating for overcurrent protection.
An electric fuse wire is a wire made up of an alloy of low melting point and having a current rating lower than that of the rating of the appliance. It is connected in series with the appliance in the phase (incoming) part.

Note:
Electric fuse is a protective device which prevents electrical equipment in the circuit by breaking the circuit when there is any type of short circuit. It also contains a fuse wire which has low resistance due to which it allows normal current to pass through it safely but if there is any short circuit, fuse will blow out i.e fuse wire can’t withstand the heat produced by that current (infinite current) so it melts and breaks down the circuit. Thus, protecting electrical devices from short circuit current.