Question

Name a substance used almost exclusively for making filaments of electric bulbs.

Answer 1

1. The melting point is the minimum temperature where a substance starts to melt.
2. An electric current heats the filament to a very high temperature. Therefore, the material of a very high melting point is used in filaments.
3. Tungsten metal has a very high melting point so it does not burn at very high temperatures.
4. The resistivity of tungsten is also very high, and hence it does not burn down at a high temperature.

Hence, tungsten is used almost exclusively for making filaments of electric bulbs.