How Does a Light Bulb Work?
The light bulb work by giving off light by converting electrical energy into light energy.
The light bulb might have been more accurately called the ‘heat bulb’ as most of its energy gets turned into heat.
Inside a light bulb, a glass rod supports a very thin, coiled wire called a filament made of hard-to-melt metal – tungsten that can stand extreme heat.
Before the bulb and its contents are sealed up tight all the air is pumped out, and a special non-burning gas is put in. This is done because the hot filament would quickly burn up if exposed to air.
When electricity passes through the tungsten filament, the filament becomes so hot that it glows with a bright light. The inside of the bulb is given a white coat to make the bulb’s light softer. This is how a light bulb work.
Light bulbs are sold according to the number of watts they use – the higher the number, the brighter the bulb is, and the more energy it uses. Despite getting hot, light bulbs don’t explode. However, the outer glass of a light bulb which has been on for some time is quite hot, and can cause minor burns, or the broken edges might cut the skin.
Another common type of light is the fluorescent lamp. A fluorescent lamp is a glass tube filled with argon gas and a trough of mercury. When electric current is passed through the gas the atoms of the gas pick up energy and radiate it in the form of ultra-violet light and some heat.
The UV light then strikes the inside of the tube, which is coated with a phosphor. The phosphor glows, giving off the light we see.
Fluorescent lamps don’t require high temperatures to produce light, like incandescent bulbs do. Energy must be used in heating the incandescent bulb, and a large part of that energy is lost as heat, not light. In the fluorescent lamp, a larger part of the energy is radiated as light.