As mentioned, only luminous objects can
produce their own light. There are, in precise 3 types of light produced from them. A
luminous object can produce incandescent light, fluorescent light or neon light.
Incandescent Light
Generally, light that is
produced from heat, sometimes until they start to glow is known as incandescent
light. Let us take an ordinary light bulb for instance. When electricity flows in
your homes, electrons start to flow inside the filament of a bulb. The filament made of
tungsten does not melt and can withstand temperatures up to over 2000 degree celsius
without melting. The filament in the bulb is in the form of a coiled coil. This produces
very high resistance. This is based on the fact that the longer a material, the higher the
resistance it possess. In this way, the tunsten filament resists the flow of electrons. It
produces what is known as electric resistance. This produces heat. When there is
sufficient heat, the tungsten glows and produces incandescent light.
Fluorescent Light
This kind of light produces
less heat and consumes much lesser electricity than incandescent light. The mechanism here
is not to principally store up heat but to utilise them. Heat is usually used to propel
and make gas molecules move contained within a tube. Inside a fluorescent lamp, substances
called phosphors are being coated on them. After absorbing ultraviolet
energy, phosphors start to glow and produce visible light. The colour that it produce will
depends on the phosphors used.
Neon Light
Ever seen brightly coloured
lights used in decoration or advertisement? They are unmistakenly neon lights.
It is cool. Similarly, when electrons pass through the various glass tubes, light is
produced. The most common type of gas used is neon gas. Light from neon lights is bright
red. In other words, the colour of the light produced depends on the gas used. For
example, mercury vapour will produce greenish-blue lights which is not much glaring.
