Luminescence is a way of producing light without giving out heat. The light is produced by electrons inside the atoms of the luminescent material. Electrons gain energy by absorbing light, or electrical energy but not heat. They then give out light as they lose that energy.
Luminescence is useful in situations where the presence of heat would potentially be dangerous. For example, in televisions, there are dyes on the inside surface of a television screen called phosphors. These can give out light without being hot. If they did give out heat, the television would quickly become a fire risk. So luminescence is quite an important source of safe lighting.
Other luminescent sources of light include 'glow in the dark' signs and some types of fluorescent light. Solar lamps may also be luminescent, they gain energy from the light that falls on them during the day and then transmit light as they lose that energy.
Luminescence is useful in situations where the presence of heat would potentially be dangerous. For example, in televisions, there are dyes on the inside surface of a television screen called phosphors. These can give out light without being hot. If they did give out heat, the television would quickly become a fire risk. So luminescence is quite an important source of safe lighting.
Other luminescent sources of light include 'glow in the dark' signs and some types of fluorescent light. Solar lamps may also be luminescent, they gain energy from the light that falls on them during the day and then transmit light as they lose that energy.