How does a bulb glow when electric current passes through it?
In the bulb, there is a thin wire, called the filament, which is made of a tungsten wire. The filament is enclosed in a glass bulb from which air has been removed. This is because the air would oxidize the filament. The filament in the bulb has resistance. The current flowing through the resistance of the bulb filament causes the filament to dissipate energy in the form of heat and light due to the hindrance caused to the flow of the electric current. The filament is actually glowing white-hot because of the energy it is dissipating, thus giving off light.
It is due to the heating effect of electric current i.e. when an electric current is passed through a conductor, it generates heat due to the hindrance caused by the conductor to the flowing current. The work done in overcoming the hindrance to the current generates heat in that conductor.
In the bulb, there is a thin wire, called the filament, which is made of a tungsten wire. The filament is enclosed in a glass bulb from which air has been removed. This is because the air would oxidize the filament. The filament in the bulb has resistance. The current flowing through the resistance of the bulb filament causes the filament to dissipate energy in the form of heat and light due to the hindrance caused to the flow of the electric current. The filament is actually glowing white-hot because of the energy it is dissipating, thus giving off light.
It is due to the heating effect of electric current i.e. when an electric current is passed through a conductor, it generates heat due to the hindrance caused by the conductor to the flowing current. The work done in overcoming the hindrance to the current generates heat in that conductor.
