Question

Why is tungsten metal used in bulbs but not in fuse wires?

Answer 1

Step 1: Tungsten and its property

1. Tungsten is a chemical element with atomic number 74.
2. It has very high Melting Point, corrosion resistance, temperature , lowest thermal expansion and inactive to react with other gases.
3. Due to the above properties, tungsten can hold a huge amount of current and as a result of the heating effect of current, it starts to glow and spreads light.

Step 2: Tungsten in Fuse wire

1. Tungsten cannot be used in fuse wire because in fuse wire the elements must have low melting point, low ohmic losses and high conductivity.
2. The tungsten will not melt in fuse wire even if the current exceeds 15 A and it may damage the appliances.

Hence, tungsten metal is used in bulbs because it can hold a lot of current and glows but in fuse wire it will not melt even if the current goes beyond 15 A.