Question

The electric fuse, used as safety device for electric appliances in house holds, is a conductor of
1. low resistance and low melting point
2. high resistance and low melting point
3. low resistance and high melting point
4. high resistance and high melting point

Answer 1

Correct Answer - Option 2 : high resistance and low melting point

CONCEPT:

• An electrical safety device that is used to protect the electrical circuit from overload is called a fuse.
• The material used for fuse elements must be of:

1. low melting point, low ohmic loss,
2. high resistivity,
3. low cost and free from detraction.
4. The material used for making fuse element has a low melting point such as tin, lead, or zinc.
5. A low melting point is, however, available with a high specific resistance metal.
6. The material mainly used for fuse element are tin, lead, silver, copper, zinc, aluminum,  and an alloy of lead and tin

EXPLANATION:

• The electrical fuse is made up of tin and lead, the mixture of these metals has high resistance and low melting point which is the characteristic of fuse wire in order to ensure the proper safety for the device. 
• Upon an increase in current in the circuit, the fuse wire melts and breaks then the electrical circuit is open, then the excess of current won't flow through the circuit hence the device is protected from the overflow of current 
• Hence, option 2 is the answer.