How do fluorescent strip lights work

Strip lighting in a classroom, hospital, business hall or kitchen is often called fluorescent lighting, although in fact it is a phosphorescent process, as above. Each bulb consists of a thin, hollow glass tube that is sealed at both ends. It contains gas such as helium, argon or krypton, and a drop of liquid mercury (about 0.5 mg of mercury per kilogram of lamp, or 0.5 parts per million). Like the neon and sodium lamps above, the pressure inside the tube is about 30 Pa, so the mercury evaporates to become a vapour. It is the mercury that yields the light, albeit indirectly. 

The reasons why the photon can be re-emitted at a different wavelength were discussed above when we introduced the topic phosphorescence. The exact 

Care the two words fluorescence and phosphorescence are employed interchangeably in everyday life, but in fact relate to different photon pathways. 

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