MCQ Detailed View

A fuse wire is a safety device used in electrical circuits to protect appliances and wiring from excessive current flow. It is designed to melt and break the circuit whenever the current exceeds safe limits, preventing fire hazards or equipment damage. The effectiveness of a fuse wire depends on its material composition, which must have low melting point and high electrical resistance compared to regular wiring.

Fuse wire is generally made of an alloy consisting of 63% tin and 37% lead. This specific composition is chosen because:

1. 
   

   Low Melting Point: The alloy melts quickly when the current becomes too high, interrupting the flow of electricity and safeguarding the circuit.

   
   


2. 
   

   Good Conductivity: It allows normal current to pass without overheating under safe operating conditions.

   
   


3. 
   

   Controlled Fusing Temperature: The combination of tin and lead ensures that the wire does not melt under normal load but reacts immediately to overcurrent.

   
   

Using pure copper or aluminum would not be suitable for fuse wires because they have higher melting points and may not melt quickly enough during excessive current flow. This could lead to overheating, damaged appliances, or even electrical fires.

The fuse wire is usually enclosed in a protective casing or fuse holder. When it melts due to overcurrent, it breaks the electrical connection, requiring replacement before the circuit can operate again. This simple yet highly effective device is an essential safety feature in household wiring, electrical panels, and many electronic devices.

Thus, the correct answer is 63% tin and 37% lead, making it the ideal material for manufacturing fuse wires due to its controlled fusing properties and reliable safety performance.