Glowing of an electric bulb is a physical change since no new substance with different properties is formed. 

Glowing of Bulb: A Physical or Chemical Change?

The glowing of a bulb is considered a physical change rather than a chemical change. It is a result of the flow of electricity through the filament of the bulb, which causes it to heat up and emit light. Let's delve into the details to understand why this phenomenon is classified as a physical change.

Physical Change:
A physical change refers to a change in the physical properties of a substance without altering its chemical composition. In the case of a bulb, the glowing occurs due to the physical properties of the filament and the flow of electricity, without any alteration in the chemical composition of the filament.

Electricity and the Filament:
When electricity is supplied to a bulb, it passes through the filament, which is usually made of tungsten. The filament is a thin wire-like structure that offers resistance to the flow of electric current. Due to this resistance, the filament begins to heat up.

Incandescence:
As the filament heats up, it reaches a temperature high enough to emit visible light. This process is known as incandescence. The high temperature causes the atoms in the filament to vibrate rapidly, which leads to the emission of photons, resulting in the visible light we observe as the glow of the bulb.

No Chemical Reactions:
During the glowing of the bulb, no chemical reactions take place within the filament. The tungsten atoms in the filament do not undergo any chemical changes or transformations. Instead, the flow of electricity causes an increase in the thermal energy of the filament, leading to incandescence.

Reversibility:
Another characteristic of a physical change is its reversibility. In the case of a glowing bulb, once the flow of electricity is stopped, the filament cools down and stops emitting light. The bulb can return to its original state, and the filament can be reused to emit light again when electricity is supplied.

Conclusion:
In conclusion, the glowing of a bulb is a physical change because it is a result of the flow of electricity causing the filament to heat up and emit light without undergoing any chemical reactions. The process is reversible, and the filament can be used repeatedly to produce light.

It is a physical change