A fuse wire must be
conducting and of low melting point
conducting and of high melting point
insulator and of high melting point
insulator and of low melting point
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC NDA-1 – 2019
– It is connected in series with the circuit, so it must be able to conduct electricity under normal operating conditions. Thus, it must be **conducting**.
– When the current flowing through the circuit exceeds a specified limit (the fuse rating), the fuse wire heats up due to the Joule effect (heat = I²Rt).
– To break the circuit and stop the excessive current flow, the fuse wire must melt when it gets too hot. This requires it to have a **low melting point**.
– If the fuse wire had a high melting point or was an insulator, it would not serve its purpose as a safety device.