photo-, phot-, -photic

(Greek: light; ultraviolet and infrared radiation; radiant energy)

photocell, photoelectric cell, electric eye
1. A device that generates electrical energy from light energy, usually as a voltage or current.
2. An instrument which converts light into electrical energy or uses it to regulate a flow of current, often incorporated into automatic control systems for doors and lighting.
3. An electronic device having an electrical output that varies in response to incident radiation; especially, to visible light.
4. A small cathode-ray tube having a fluorescent pattern whose size varies with the voltage applied to the grid.

It is used in radio receivers to indicate accuracy of tuning and as a modulation indicator in some tape recorders.

5. An electric eye can operate a mechanism so as to open a door when its invisible beam is interrupted by the approach of a person and includes a photoelectric cell which is used as an automatic controlling appliance.

It is also used in motion pictures, television, and many other industries.

A cell capable of perceiving the presence of light.
Referring to the chemical properties of light; chemically reactive in the presence of light or other radiation.
1. The branch of chemistry having to do with the effect of light, or other radiant energy, while producing a chemical action, as with photographs.
2. The scientific study of chemical changes caused, or influenced, by the effects of light.
The treatment of cancer by intravenous injection of a photosensitizing agent; such as, hematoporphyrin, followed by exposure to visible light of superficial tumors or deep tumors by a fiberotic probe.
Pertaining to, or referring to, the chromatic or coloring action of light; pertaining to or produced by photochromy.
1. A reference to a material, such as certain glass or film, which turns dark when exposed to light and returns to its normal transparency with the removal of the light source.
2. Relating to, or characterized by, changing color as a result of exposure to incident radiation.
photochromic lens
A light-sensitive spectacle lens that reduces light transmission in sunlight and increases transmission in reduced light.
Changing color as a result of exposure to incident radiation; a property of certain organisms when exposed to the light of a particular wavelength.
1. A microorganism whose pigmentation develops as a result of exposure to light.
2. a mycobacterium that forms yellow or orange colonies when grown in the light.
Forming pigment when cultured in the light.

This characteristic is useful for classifying pathogenic mycobacteria (includes the bacteria that cause tuberculosis and leprosy).

photochronograph (s) (noun), photochronographs (pl)
An instrument for taking a series of instantaneous photographs at regular short intervals of time, also each of the photographs so taken: A photochronograph is a device by which a beam of light is caused to produce a photographic image at some precise instant of time, for example, so as to show the exact time at which a star crosses the meridian.
photochronography (s) (noun) (no pl)
The art of recording or measuring intervals of time with the photochronograph: Bob's hobby was photography, but he was especially interested in photochronography whereby he could take instantaneous photos at regular and in short intervals of time, like birds or horses in motion.
Moving in response to the stimulus of light.
photocoagulation (s) (noun), photocoagulations (pl)
Condensation of protein material by the controlled use of an intense beam of light: Photocoagulation is used especially in the treatment of retinal detachment and the destruction of abnormal retinal vessels, or of intraocular tumor masses.

Photocoagulation is a technique that uses intense light energy, as from a laser, to produce scar tissue used in treating certain eye disorders, in medical and biological research, etc.

Etymologically related "light, shine, glow" word families: ethero-; fulg-; luco-; lumen-, lum-; luna, luni-; lustr-; phengo-; pheno-; phospho-; scinti-, scintill-; splendo-.