26 relations: Brightness, Candela, Electric light, Electromagnetic radiation, Fluorescent lamp, Human eye, Incandescent light bulb, Infrared, International System of Units, Kerosene lamp, Laser, Light, Light-emitting diode, Lumen (unit), Luminosity function, Luminous efficacy, Luminous intensity, Metal-halide lamp, Photometry (optics), Power (physics), Radiant flux, Steradian, Ultraviolet, Wavelength, Weight function, Weighting.
Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light.
The candela (or; symbol: cd) is the base unit of luminous intensity in the International System of Units (SI); that is, luminous power per unit solid angle emitted by a point light source in a particular direction.
An electric light is a device that produces visible light from electric current.
In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space-time, carrying electromagnetic radiant energy.
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light.
The human eye is an organ which reacts to light and pressure.
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light (incandescence).
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions). It is sometimes called infrared light.
The International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement.
A kerosene lamp (also known as a paraffin lamp in some countries) is a type of lighting device that uses kerosene (paraffin) as a fuel.
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.
Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.
A light-emitting diode (LED) is a two-lead semiconductor light source.
The lumen (symbol: lm) is the SI derived unit of luminous flux, a measure of the total quantity of visible light emitted by a source.
A luminosity function or luminous efficiency function describes the average spectral sensitivity of human visual perception of brightness.
Luminous efficacy is a measure of how well a light source produces visible light.
In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye.
A metal-halide lamp is an electrical lamp that produces light by an electric arc through a gaseous mixture of vaporized mercury and metal halides (compounds of metals with bromine or iodine).
Photometry is the science of the measurement of light, in terms of its perceived brightness to the human eye.
In physics, power is the rate of doing work, the amount of energy transferred per unit time.
In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted or received, per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength.
Ultraviolet (UV) is electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays.
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
A weight function is a mathematical device used when performing a sum, integral, or average to give some elements more "weight" or influence on the result than other elements in the same set.
The process of weighting involves emphasizing the contribution of some aspects of a phenomenon (or of a set of data) to a final effect or result, giving them more weight in the analysis.