subject: Simply Introduction Of Optical Terminology Knowledge [print this page] 1. Luminous intensity (brightness) What is the meaning?
A: The luminous intensity (brightness, I) is defined as: point of light in the luminous intensity up a party, that is luminous body in unit time by the amount of light injection, also referred to as light, commonly used units for the candlelight (cd, candela) , an international definition of a candlelight vigil for whale oil candles made from 120 per hour burning cold cell (grain) of the light emitted by a cell of cold equal to 0.0648 grams
2. Luminous intensity (brightness) What is the unit?
A: The common unit of luminous intensity candlelight (cd, candela), the international standard candles (lcd) is defined as an ideal blackbody at the freezing point of platinum temperature (1769 ), the perpendicular to the blackbody (its specific surface area of 1m2) direction 60 one ten thousandth of the light, the so-called ideal black body radiation is the rate of objects equal to 1, objects can be absorbed by all the radiation energy out, so that the temperature has remained fixed uniform, international standard candles (candela) and the old standard candles (candle ) for the exchange of relations 1candela = 0.981candle
3. What is meant by flux? What is the unit flux?
A: The luminous flux () is defined as: point source and non-point source in unit time given by the energy, which may have a visual person (who can feel out of the radiation flux) that is known as flux. The unit of luminous flux lumens (abbreviated lm), 1 lm (lumen or lm) is defined as an international standard candles of light in the unit by three-dimensional arc angle of the flux through, the whole area of spherical 4R2, so first-class equivalent to a prescribed luminous flux The luminous flux emitted by a candle light vigil 1/4, or have a spherical 4, therefore in accordance with the lumen of a cd, we can see the definition of the point radiation source will 4 lumens, that is, (lm) = 4I (candlelight), it is assumed that for small three-dimensional arc angle in flux within the solid angle , while = I
4. 1 feet What is the meaning of candlelight?
A: 1 feet away from a candlelight candlelight means of the light source (point source or non-point source) and one feet away and the surface of the orthogonal light illumination, the abbreviation for 1ftc (1 lm/ft2, lm / ft 2) , that is to receive per square foot by 1 lumen luminous flux at the time of illumination, and 1ftc = 10.76 lux
5. 1 meters What is the meaning of candlelight?
A: The one-meter candlelight candlelight refers to the distance of a light source (point source or non-point source) with one meter far from the surface of the orthogonal light illumination, known as the lux (lux, also written in lx), each received by the square of 1 lumen luminous flux at the time of illumination (lumens / m 2)
6. 1 lux What is the meaning?
A: per square meter received by 1 lumen luminous flux at the time of illumination
7. What is the meaning of illumination?
A: illuminance (E) is defined as: objects illuminated unit exposed area of the luminous flux received by, or by light irradiation of the objects in unit time per unit area of the light received by the unit in meters or feet candle candlelight light (ftc) .
8. Illuminance and light, What is the relationship between the distance between?
A: The intensity and luminosity, is the relationship between the distance: E (illuminance) = I (light) / r2 (distance squared)
9. Was the illumination according to body size and what factors?
A: According to the body by illumination with light source and the luminous intensity and according to the distance between the light source, while according to the body with the color, surface properties and surface area size
