Health is wealthMercury Vapor Lamp
Mercury Vapor Lamp is from fluorescence emission. The mechanism in mercury vapor lamp is more involved and sequential. The sputtered electrons from the filaments, after having been accelerated by high voltage, hit the mercury atoms. Here also, the excited electrons of mercury atoms relax by emitting characteristic but ultraviolet (254nm, invisible) light. The photons of this ultraviolet light fall on the fluorescent layer on the inner walls of the tube and excite the molecular bonds of the fluorescent material to various electronic and vibrational energy states. Hence, the light from the mercury vapor lamp is white. It works through the combined effect of electric discharge through mercury vapors and fluorescence from phosphors (luminescent materials).
On the other hand, a mercury vapor lamp is quite suitable for lighting applications. This is because; the mercury vapor lamp can feed almost the entire visible region (380-780 nm) of the human visual system. Conventional fluorescent lamps can also be called as low-pressure mercury discharge lamps. In this system, when electric discharge strikes mercury vapors held at low pressure ( a few mm of mercury) it produces a lot of ultraviolet radiation dominantly at 254 nm inside the column of the discharge tube. This UV radiation when impinging on the white coating made of fluorescent materials coated inside the discharge column of the tube will generate white light (called daylight). Light output from a fluorescent lamp is moderate (60 lumens/watt) while the color-rendering index is high.
On the other hand, a mercury vapor lamp is quite suitable for lighting applications. This is because; the mercury vapor lamp can feed almost the entire visible region (380-780 nm) of the human visual system. Conventional fluorescent lamps can also be called as low-pressure mercury discharge lamps. In this system, when electric discharge strikes mercury vapors held at low pressure ( a few mm of mercury) it produces a lot of ultraviolet radiation dominantly at 254 nm inside the column of the discharge tube. This UV radiation when impinging on the white coating made of fluorescent materials coated inside the discharge column of the tube will generate white light (called daylight). Light output from a fluorescent lamp is moderate (60 lumens/watt) while the color-rendering index is high.
