Fluorescence

A variety of luminescence. Certain materials display an effect of producing visible electromagnetic light, when irradiated by ultraviolet light, cathode ray or X-rays, or other forms of radiation of an appropriate wavelength. The emitted light has another form of energy different to absorbing light. The fluorescence phenomenon ceases immediately, when the source of ray is removed, if the effect continues after removal of the energy source it is then termed phosphorescence.