Mercury lamps get dimmer over time and rarely burn out so it is wise to replace them and restore light level.
High pressure mercury vapour lamp colour.
When outside coated or color corrected lamps can usually be identified by a blue halo around the light being given off.
There is also an increase in red color e g due to the continuous radiation in ultra high pressure mercury vapor lamps usually greater than 200 atm which has found application in modern compact projection devices.
Mercury vapor lamps were the first high intensity discharge lamps to be commercially available for a wide variety of lighting applications.
1901 the first commercial mercury vapor lamp peter cooper hewitt new york city had a history of innovations in other fields and when he set about on the project of the mercury vapor lamp in 1898 it only took 3 years to develop the first reliable lamp with a acceptable color of light.
The light output of a self ballasted lamp is a blend of incandescent and mercury vapor light.
High pressure mercury the mercury vapour standard range of high pressure mercury lamps utilise yttrium vanadate phosphor and provide a neutral white colour temperature of 4000k.
Mercury vapor lamps are gas discharge lamps that uses an electric arc through vaporized mercury to produce light.
Again transition of the electrons requires least amount of input energy from a colliding electron.
The range provides a low cost white lighting solution operating on a simple mercury choke circuit.
Mercury vapor lamps feature low initial cost but have higher operating costs than hps or metal halide due to its lower efficiency.
In case of fluorescent lamp the mercury vapour pressure is maintained at lower level such that 60 of the total input energy gets converted into 253 7 nm single line.
As pressure increases the chance of multiple collisions gets increased.
Further improvement is achieved in many of the lamp types by the addition of a phosphor coating to the inside surface of the outer bulb.
