Question

Why do we use thin and long tungsten in the filament of an electric bulb?

Answer 1

1. Tungsten is used in electric bulbs because it has a high melting point and it does not oxidize.
2. Thus tungsten filament does not melt even when a large amount of heat is produced due to the passage of current through the filament (via the heating effect of current).
3. Tungsten has low resistivity and as such only a thin wire filament will high resistance necessary to produce a large amount of heat to light the bulb brilliantly.
4. Further, tungsten has a very high melting point (3300K), and as such, the filament will not burn at the high temperature (2400K) at which it becomes incandescent.