Question

In a safety fuse, the temperature to which the wire gets heated does not depend upon

• A. the radius of the wire
• B. the length of the fuse wire
• C. the type of alloy used
• D. the magnitude of the current

Answer 1

The correct option is B

the length of the fuse wire

Explanation for correct option:

Option (B) the length of the fuse wire

1. Fuse is a safety device to protect electrical devices.
2. Fuse basically is made of small wire with high resistivity and low melting point.
3. It works on the principle of the heating effect of electric current and uses Joule's law of heating.
4. So, we can say that rise the current in the fuse wire, the more the heat produced.
5. When more current flows through the wire, it heats up more and because of the low melting point, it will start melting and break up the circuit.
6. Thus, the melting of fuse wire does not depend on the length.

Explanation for incorrect options:

1. While the fuse wire is selected, usually the wire with a high resistivity is used; thus depending on the nature of the alloy used. Hence, option C. is incorrect.
2. The resistance of the fuse depends on the area of the cross-section, in turn, the radius of the wire. Thus, option A. is incorrect.

Hence, option B is the correct answer.