What is a LED?
A light emitting diode (LED) is a semiconductor device that emits visible light when electrical current passes through it, it is a special kind of diode.
What color of light can LED emit?
Most LEDs are monochromatic. Light color is associated with the light wavelength. LEDs made with different semiconductor materials emit lights in different wavelengths. LED light wavelengths range from 400 nanometers (blue) to 800 nanometers (red). The colors of popularly available LEDs in the market are red, orange, amber, yellow, green, blue and white.