Question

The rating of the fuse depends on the:
(A) Thickness of the fuse wire
(B) Length of the fuse wire
(C) Both A and B
(D) None of the above.

Answer 1

Hint:Fuse wires are very important parts as far as an electric circuit is considered. A fuse wire is nothing but a very thin wire with a very low melting point value. It is used to protect the connected electrical appliances from destruction which might take place as a result of the heavy voltage.

Complete step by step solution:
-An electric fuse is a piece of wire that is capable of interrupting the flow of current in the circuit. The wire has a high value of resistivity and a low value of melting point. Hence, during excessive current flow, the wire melts when overheating occurs and breaks the connection, thereby protecting the circuit.
-The maximum current that flows through a fuse wire without causing it to melt is called its rating. We know that the resistance of the wire is directly proportional to its length and inversely proportional to its area. As the length increases, the resistance increases but the melting or fusing remains the same. But when the thickness that is the diameter of the wire increases, the area increases and the resistance decreases, causing a variation in the fusing or melting. Hence we can conclude that the rating of the fuse is dependent on the thickness of the wire.

Thus option A is the correct answer.

Note:Fuse wire is made of delicate materials like zinc, copper or aluminium alloys. It is always connected in series to ensure safety, as the current initially passes through the wire and then to the appliance.