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∙ 8y agoThe mercury vapor is used for the gas discharged - in other words, when the electrical current passes through a plasma, light is produced.
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What will happen if mercury lamp is used instead of sodium lamp in plane diffraction grating exp?
for diffraction grating mercury lamp is used not sodium lamp.
What liquid metal used to be in thermometers?
Mercury. The metal gives off poisonous vapours - and has largely been replaced by alcohol.
What element was used during the California gold rush extract gold from mine deposits?
Mercury was used to dissolve gold from the ore. The mercury/gold mixture was then heated to drive off the mercury leaving the gold. The mercury vapours were detrimental to the environment and the jhealth of the prospectors
How a barometer can be used to measure the vapor pressure of a liquid?
A mercury thermometer, that is a barometer can be used to measure vapor pressure. Initially, a proper temperature must be recorded. Then the liquid should be injected into the mercury column. This new measurement subtracted from the original will yield the vapor pressure of a liquid.
Why it is not proper to regard gaseous state of amonia as vapours?
Vapor is properly used to refer to a gaseous form of a substance which is liquid or solid under standard temperature and pressure. Because ammonia is a gas at STP, it is not properly called a vapor.
What kind of laser is used in diffraction grating experiment?
laser is not used in that experiment. that was mercury lamp which is used for that exp.
What alkali metal is used in street lights?
Sodium (chem symbol = Na) Mercury vapor is also used in street lights. Low pressure sodium vapor street lights are amber/yellow in color, high pressure sodium lights are white and mercury vapor lights glow blueish white.
What is Hg used for?
Mercury can be used to make thermometers, barometers and other scientific instruments. Mercury conducts electricity and is used to make silent, position dependent switches. Mercury vapor is used in streetlights, fluorescent lamps and advertising signs.
What does turning on a fluorescent lamp create?
A plasma arc of argon gas and/or other ions, such as mercury vapour, depending on the gas mixture used in the lamp.
What is the Working principle of mercury vapour lamp?
The mercury in the tube is a liquid at normal temperatures. It needs to be vaporized and ionized before the tube will conduct electricity and the arc can start. So, like fluorescent tubes, mercury vapor lamps require a starter, which is usually contained within the mercury vapor lamp itself. A third electrodeis mounted near one of the main electrodes and connected through a resistor to the other main electrode. In addition to the mercury, the tube is filled with argon gas at low pressure. When power is applied, there is sufficient voltage to ionize the argon and strike a small arc between the starting electrode and the adjacent main electrode. This starting arc discharge heats the mercury and eventually provides enough ionized mercury to strike an arc between the main electrodes. This process takes from 4 to 7 minutes, so mercury lamps are slow starting. Some bulbs include a thermal switch which shorts the starting electrode to the adjacent main electrode, extinguishing the starting arc once the main arc strikes.The mercury vapor lamp is a negative resistance device. This means its resistance decreases as the current through the tube increases. So if the lamp is connected directly to a constant-voltage source like the power lines, the current through it will increase until it destroys itself. Therefore it requires a ballast to limit the current through it. Mercury vapor lamp ballasts are similar to the ballasts used with fluorescent lamps. In fact, the first British fluorescent lamps were designed to operate from 80-watt mercury vapor ballasts.Variation: Metal halideA very closely related lamp design called the metal halide lamp uses various compounds in an amalgam with the mercury. Sodium iodide and scandium iodide are commonly in use. These lamps can produce much better quality light without resorting to phosphors. If they use a starting electrode, there is always a thermal shorting switch to eliminate any electrical potential between the main electrode and the starting electrode once the lamp is lit. (This electrical potential in the presence of the halides can cause the failure of the glass/metal seal). More modern metal halide systems do not use a separate starting electrode; instead, the lamp is started using high voltage pulses as with high-pressure sodium vapor lamps. "MetalArc" is Osram Sylvania's trademark for their metal halide lamps; "Arcstream" and "MultiVapor" are General Electric's trademark. Besides their use in traditional outdoor lighting, these lamps now appear in most computer and video projectors. However, Philips' UHP lamp, introduced in 1995, contains only mercury. As an example of application and efficiency of mercury lamps, the 61" Samsung DLP rear projection TV (HL-S6187W) uses a 150-watt Osram P-VIP lamp. Self-ballasted (SB) lampsThere are mercury vapor lamps with a filament inside connected in series with the arc tube that functions as an electrical ballast. This is the only kind of mercury vapor lamp that should be connected directly to the mains without an external ballast. These lamps have only the same or slightly higher efficiency than incandescent lamps of similar size, but have a longer life. They give light immediately on startup, but usually needs a few minutes to restrike if power has been interrupted. Because of the light emitted by the filament, they have slightly better color rendering properties than mercury vapor lamps. The color temperature is higher than incandescent lamps.
How might you distinguish a sodium vapor streetlight from a mercury vapor streetlight?
Mercury vapor streetlights, used since the 1940s, glow a greenish white. Sodium vapor streetlights, which have gradually replaced most of the MV streetlights in the US, glow orange. Another two, metal halide and LED, glow completely white.
What are mercury thermometers used for?
If the bulb is red, blue, purple, green or any other color, it is not a mercury thermometer. Mercury thermometerscan be used to determine body temperature (fever thermometers), liquid temperature, and vapor temperature.
