fluorescent lamp

Definition: Type of light source which exploits phenomenon of fluorescence. * Tube fitted with electrodes is filled with gas e.g. mercury vapour: when a sufficiently high voltage is applied between electrodes, current flows through the gas, exciting it to produce ultraviolet radiation which strikes coating of fluorescent substance or phosphor on inside of tube: this in turn radiates visible light. * Due to nature of its production, only few wavelengths of light are present in light from fluorescent lamps i.e. they show highly discontinuous spectra.

Previous Term: fluorescence photography  Next Term: f-theta lens