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Incandescent vs Fluorescent Light: Types of Luminescence

Incandescent vs Fluorescent light are two major types of light emitted by bulbs. Fluorescent lighting was once mostly used in commercial and industrial environments, but it is now becoming more common in homes. Luminescence is defined as a form of cold body radiations in which there happens a spontaneous emission of light from a substance which is not resulted by heat or “cold light (light causing no heat)”. This thing makes it different from incandescence, in which light is emitted by heat. It can be due to chemical reactions, electrical energy, subatomic energy and stress on a crystal.

Luminescence can be observed in various things like

  • Neon and fluorescent lamps including TV, Radar, X-ray fluoroscope screens
  • Organic substances
  • Certain pigments

Luminescent materials like phosphorous are materials that emit light (infrared to ultraviolet) under external excitation of energy. The incident energy will then be re-emitted in the form of electromagnetic radiation in the form of high energy electron, photons, or electric field.

How luminescence occurs?

Luminescence and Incandescence, How Does Luminescence Occurs?

Luminescence emission happens when an appropriate material has absorbed sufficient energy to move to excited sources, by sources like UV or x-rays, electron beams and so on. When the energy is absorbed by the material then its atoms go to excited state. Since excited state is unstable so after some time, when this atom returns back to its ground state then light, heat and sometimes both are emitted. Only outermost orbiting electrons are involved in this excitation.

Types of luminescence

  • Photoluminescence: It is resulted by the absorption of photons.
  • Florescence: a type of photoluminescence which is based on singlet- singlet electronic relaxation in nanoseconds.
  • Phosphorescence: a type of luminescence which is based on triplet- singlet electron relaxation in mili-seconds to hrs.
  • Radio-luminescence: it is resulted by bombarding a substance by ionizing radiations.
  • Thermo-luminescence: in it, energy absorbed by material is released when it is heated up.
  • Cryo-luminescence: emission of light photons when an object is cooled like in case of wulfenite.
  • LEDs: they emit light when electricity is passed from them (electro- luminescence).

Phosphorus is a material which emits light when it is irradiated by higher energy electromagnetic radiations.

Light as Electromagnetic Wave: Properties of Light

Luminescence and incandescence

What is luminescence?

This process happens by the excitations of electrons to excited states but it does not involve agitation of atoms. It is process of emission of light at normal or cooler temperature, so it is termed as cold light. Light is created when energy is released by the return of electron from excited to ground state. Luminescence is an efficient way of production of light as no energy is wasted as heat. Its examples include florescent light bulbs, glow in dark toys and fireflies.

Luminescence and Incandescence, How Does Luminescence Occurs?

What is incandescence?

A process having emission of light having high state of agitation, is called incandescence or the emission of light when temperature of object rises too much. In incandescence, much part of energy is wasted in form of heat, so it is not an efficient way and is termed as “hot light”. Its examples include red burners in electric stove and white filament in bulb.

Electrons in atoms of a material even vibrate at room temperature, but this vibration just produces heat radiations lying in IR region of EM spectrum. If temperature is increased, then these radiations shift to visible region.

Incandescent vs Fluorescent Light bulbs

Incandescent vs Fluorescent Light are different just by the source which produces light in both. Incandescent bulbs and fluorescent lamps are the two most popular styles of lighting fixtures today. Incandescent bulbs are old, while fluorescent lamps are modern and are replacing incandescent bulbs in many applications. The most significant distinction between the two is how they generate light. Light is generated by incandescent bulbs by heating a metallic filament until it begins to radiate light. Fluorescent lamps, on the other hand, emit light by igniting a gas and causing it to glow.

In comparison to incandescent bulbs, the newer and more technologically advanced fluorescent lamps have better characteristics, the most significant of which is performance. An incandescent bulb uses 4 to 8 times the amount of energy as a fluorescent lamp to generate the same amount of illumination. Incandescent bulbs lose a lot of energy, which is converted to heat. Heat generation is often desirable, such as in incubators, but it is often a waste of energy and resources.

While fluorescent lamps are less expensive in the long run because they last longer and use less energy, the initial cost of using them is significantly higher than incandescent bulbs.

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