What's the difference between a halogen and incandescent bulb?
Firstly it is better to define what Incandescent is:
This well-known lighting type is the most dated and least efficient because of their energy consumption and the rate of their productivity. Basically incandescent bulbs work with filament that electric current passes through and then glow happened. The issue is, only a small portion of the energy is converted into usable light and larger portion of energy created considerable amount of heat.
In incandescent bulbs the gas composition is nitrogen and argon and krypton
During operation of incandescent bulb, the tungsten evaporating from the hot filament condenses on the cooler inside bulb wall, causing the bulb to blacken. This blackening process continuously reduces the light out-put over the life of the lamp and this is one of disadvantages for incandescent bulb.
Halogens bulbs are technically incandescent light bulbs in terms of how they create light but halogen bulbs come with a few modifications to eliminate the blackening problem mentioned above.
In both of them the filament is heated sufficiently to turn on the light. The difference between the two is the composition of the glass and the gas inside the envelope.
Some modification on Halogen bulbs:
The bulb, made of fused quartz instead of soda lime glass, is consist of same inert gases as incandescent lamps but it mixed with small amounts of a halogen gas (usually less than 1% bromine). And this modification is a key to avoid blackening the envelope.