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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).
How do fluorescent lamps give out white light?
However, since ultraviolet rays are not visible to the human eyes, the inside of the glass tube is coated with a fluorescent material that converts ultraviolet rays to visible light. It is this coating that causes fluorescent lamps to glow white.
Can a fluorescent light work without a starter?
Can a fluorescent lamp work without a starter? Some modern fluorescent lights do work without a starter because they come pre-equipped with a ballast that has extra windings. It constantly supplies a small amount of voltage to give heat to the filaments.
How does a fluorescent tube work a level physics?
Fluorescent tubes are filled with low pressure mercury, when an electric current is passed through, the electrons in mercury are excited and move to a high energy level, this high level state is unstable and so the electron moves back to its original state, but on doing so, it emits an electromagnetic wave with energy.
What part of the fluorescent that initiates the light?
In a CFL, an electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light that excites a fluorescent coating (called phosphor) on the inside of the tube, which then emits visible light.
What’s inside a fluorescent light 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 is the normal life of a fluorescent lamp?
Typical Average Rated Life for Various Types of Bulbs Incandescent 750-2,000 hours Fluorescent 24,000-36,000 hours HID 10,000-24,000 hours Compact Fluorescent Plug-in 10,000-20,000 hours.
Is it the starter or the ballast?
In older fluorescent fixtures, the ballast, or choke, is a transformer that limits the current flowing into the tube, while the starter provides the high voltage needed to excite the tube when it is turned on.
How does ballast work?
In a fluorescent lighting system, the ballast regulates the current to the lamps and provides sufficient voltage to start the lamps. Once the arc is established, the ballast quickly reduces the voltage and regulates the electric current to produce a steady light output.
When the fluorescent is already lighted What do you think will happen if we remove the starter?
Tube light will not become off if you remove starter. The starter is required only at beginning to make light to glow. If you remove starter while the light is glowing it will not affect the light. The light will continue to glow.
How does a fluorescent tube produce photons?
As electrons and charged atoms move through the tube, some of them will collide with the gaseous mercury atoms. These collisions excite the atoms, bumping electrons up to higher energy levels. When the electrons return to their original energy level, they release light photons.
How are electrons excited in a fluorescent tube?
(i) As they pass through the fluorescent tube, they collide with the mercury atoms within it and this collision transfers energy to the atom. This energy transfer allows the atom’s orbiting electrons to move to a higher energy state thus exciting the atom.
Why is there low pressure in a fluorescent tube?
The initial high voltage burst is necessary to produce electrons with enough kinetic eergy to ionise the mercury atoms – the atoms in the gas need to be sparse enough (low pressure) so that KE can be built up to a level that will allow ionisation of the mercury atoms.
What is fluorescent lamp wiring?
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow.
What are the parts and function of the fluorescent lamp?
General lighting There are two very distinct parts to fluorescent lighting: the tube and the fitting. Fluorescent tubes ionise mercury vapour to produce ultraviolet light, which is converted to visible light by the phosphor coating on the inside face of the tube.
What are the five parts of a fluorescent lamp?
Compact fluorescent components consist of cover, coil glass tube, phosphor coating, mercury vapor, ballast, ballast cover, and base.
What happens if you breathe in a broken fluorescent bulb?
Persons in rooms after breakage of a CFL may be exposed to mercury by inhalation and by oral intake. After inhalation, more than 80% of inhaled Hg0 vapour is absorbed by the lungs. Ingested Hg0 is poorly absorbed in the gastrointestinal tract (less than 0.01%).
What happens if you break a fluorescent bulb?
Compact fluorescent light bulbs (CFLs) use dramatically less energy than incandescent bulbs and reduce greenhouse gas emissions. But they also contain mercury – a dangerous toxin. If a CFL breaks, some of the mercury that’s contained in the bulb will evaporate into the air.
How do fluorescent materials work?
Fluorescent materials produce light instantly, when the atoms inside them absorb energy and become “excited.” When the atoms return to normal, in as little as a hundred thousandth of a second, they give out the energy that excited them as tiny particles of light called photons.
Are LED lights better than fluorescent?
LEDs are up to 50% more efficient than fluorescent lights – so they use less energy. Translation: Dramatically smaller electric bills. LEDs usually last at least twice as long as fluorescents, which means they need to be changed less often.
What is the normal life of a fluorescent lamp * A 2000 hours B 3500 hours c 7500 hours D 10000 hours?
7500 hours – Normal life of a fluorescent lamp.
