Answer:
Light sources
Something that produces light is called a light source. There are two main kinds of light sources:
- Incandescent sources use heat to produce light. Nearly all solids, liquids and gases will start to glow with a dull red colour once they reach a temperature of about 525 °C. At about 2300 °C, the filament in a light bulb will start to produce all of the colours of the visible spectrum, so it will look white. The Sun, stars, a flame and molten metal are all incandescent.
- Luminescent sources are normally cooler and can be produced by chemical reactions, such as in a glowstick or a glow-worm. Other luminescent sources include a computer screen, fluorescent lights and LEDs.
