What are discharge lamps? (metal halide, sodium, mercury)

Discharge lamps are light sources that generate light by emitting an electrical discharge through ionized gas and other substances such as metal halide, sodium and mercury. Many different colours of light can be produced by discharge lamps – the colour varies depending on various factors such as emission spectra of the atoms that make up the gas, the pressure of the gas and more. When mercury is used, a light blue or ultraviolet light is created. With sodium, a bright orange light is produced.