Which process takes place in fluorescent tube?

Which process takes place in fluorescent tube?

An electric current in the gas energizes mercury vapor which delivers ultraviolet radiation through discharge process and the ultraviolet radiation causes the phosphor coating of the lamp inner wall to radiate visible light.

How is light produced in a fluorescent tube?

A fluorescent lamp generates light from collisions in a hot gas (‘plasma’) of free accelerated electrons with atoms– typically mercury – in which electrons are bumped up to higher energy levels and then fall back while emitting at two UV emission lines (254 nm and 185 nm).

What caused the light produced by the fluorescent?

Fluorescent lamps are slender glass tubes coated with fluorescent material on their inner surfaces. Next, a small gas discharge lamp inside the fluorescent lamp turns off; electrons are emitted from the electrode and they begin to flow toward the positive electrode. It is these electrons that produce ultraviolet light.

How does mercury work in a fluorescent light?

Fluorescent lamps work by ionizing mercury vapor in a glass tube. This causes electrons in the gas to emit photons at UV frequencies. The UV light is converted into standard visible light using a phosphor coating on the inside of the tube.

Do fluorescent tubes contain mercury?

On average, CFLs contain about four milligrams of mercury sealed within the glass tubing. No mercury is released when the bulbs are intact (i.e., not broken) or in use, but mercury vapor and very small beads of mercury can be released when a CFL is broken.

What is inside a fluorescent tube?

A fluorescent lamp consists of a glass tube filled with a mixture of argon and mercury vapour. The inside of the tube is coated with phosphors, substances that absorb ultraviolet radiation and fluoresce (reradiate the energy as visible light).

What’s inside a fluorescent tube light?

A fluorescent lamp consists of a glass tube filled with a mixture of argon and mercury vapour. Metal electrodes at each end are coated with an alkaline earth oxide that gives off electrons easily. When current flows through the gas between the electrodes, the gas is ionized and emits ultraviolet radiation.

What is inside a fluorescent light ballast?

A magnetic ballast (also called a choke) contains a coil of copper wire. The magnetic field produced by the wire traps most of the current so only the right amount gets through to the fluorescent light. That amount can fluctuate depending on the thickness and length of the copper wire.

What type of mercury is in fluorescent bulbs?

Release of Mercury From Broken Fluorescent Bulbs The primary human exposure is from ingestion of fish contami- nated with methyl mercury. However, exposures to elemental mercury vapor and mercury compounds via inhalation and dermal contact may also occur. Like many products, fluorescent bulbs contain mercury.

Where is mercury in fluorescent bulbs?

Approximately 99% of the mercury is typically contained in the phosphor, especially on lamps that are near their end of life.

Do fluorescent lights contain mercury?

How much mercury is in a fluorescent tube?

The amount of mercury in a fluorescent lamp varies from 3 to 46 mg, depending on lamp size and age. Newer lamps contain less mercury and the 3–4 mg versions are sold as low-mercury types. A typical 2006-era 4 ft (122 cm) T-12 fluorescent lamp (i.e. F34T12) contains about 5 milligrams of mercury.

How does a mercury vapor lamp work?

Low Pressure: The first mercury vapor lamps were in a lower pressure tube. One would tip the lamp, and electrical contacts on each side of the lamp would send electricity through a liquid mercury which started the lamp.

How do fluorescent tubes get their color?

The inside of the tube is coated with a phosphorous material that emits visible light when excited with UV and the tube gives off light. By carefully selecting the fluorescent powders (called “phosphors”), the manufacturer of the light can tailor the light’s coloration.

Can we replace mercury in fluorescent lamps with xenon?

OSRAM undertook one of the most recent and ambitious attempts to replace mercury in fluorescent lamps. During the last decade, a flat, very thin lamp was developed using the rare gas xenon instead of mercury vapor. As with other fluorescent lamps, it also made use of a phosphor layer for the conversion of UV into visible light.

Why is mercury used to make light bulbs?

The reason for this is based on the correlation between the light which is emitted by the mercury discharge and the phosphors available. The physical properties of mercury are unique in this respect, because this metallic element turns to vapor at the operating temperature of the lamp.