![]() The height of the bulb installation and the presence or absence of the lampshade have a great influence on the light intensity. Generally, when there is a lampshade and the lamp height is 2.0~2.4m (the bulb distance is 1.5 times the height), 1W bulbs are required for every 0.37㎡ area, or 2.7W bulbs are required for 1㎡ area, which can provide 10.76 lx. the poor quality and darkness of the bulb will reduce many lumens, so only about 50% of the lumens can be used. In the light emitted by an incandescent bulb without a lampshade, about 30% of the lumens are absorbed by walls, ceilings, equipment, etc. The luminous efficiency of the fluorescent lamp is 3 to 4 times that of the incandescent lamp, and the life span is 9 times that of the incandescent lamp, but the price is higher. Small bulbs can emit more lumens and large bulbs are less. Incandescent lamps can emit approximately 12.56 lx of light per watt, but the value varies with the size of the bulb. Under direct sunlight in summer, the light intensity can reach 60,000 to 100,000 lx, outdoor with no sun 10,000 to 10,000 lx, bright indoor in summer 100 to 550lx, and at night under the full moon it is 0.2lx. That is, the ratio of the luminous flux obtained on the surface of the object to the illuminated area, the unit is lux Ix (1 lux is the illuminance produced by the luminous flux of 1 lumen evenly irradiated on an area of 1 square meter) or foot candle fc (1 foot candle is 1 The luminous flux of lumens uniformly illuminates the illuminance produced on an area of 1 square foot), 1 fc=10.76 lx. Illuminance is the degree to which an object is illuminated. The light energy radiated by the light source per unit time is called the luminous flux of the light source, and its unit is lumens (the amount of light on a 1 square foot area where each point is 1 foot away from a 1 candle light source is 1 lumen). The amount of luminous flux transmitted by a light source within a solid angle in a certain direction. The sum of the bright period in a photoperiod is the photoperiod. In natural light, the sunlight time (bright period) is generally calculated as the sunshine time in artificial light, the light exposure time is the light time, and the 24h light cycle is the natural light cycle the longer or shorter than 24h is called unnatural light Cycle if there is only one bright period and one dark period within 24h, it is called single-period illumination if there are two or more bright or dark periods within 24h, it is called intermittent illumination. The time with light is the bright period, and the time without light is the dark period. In nature, 24 hours a day and night is a photoperiod. Sunlight is natural lighting, and light lighting is artificial lighting. Natural lighting and artificial lighting. ![]() But today’s definition has changed: heating with a black luminous body of one cubic centimeter until the luminous body melts into a liquid, 1/60 of the amount of light emitted is the standard light source, and candlelight is the standard light source. The concept of candlelight was first invented by the British, and it is a unit of luminous intensity.Īt that time, the British used a pound of white wax to create a one-foot-long candle to define the unit of candlelight. Lumen is a unit of luminous flux.Ī point light source with a luminous intensity of 1 candela has a luminous flux of “1 lumen” per unit solid angle (1 steradian).Ĭandlelight (Candela), transliteration “Candela”. For an object that is uniformly illuminated by light, when the luminous flux obtained on an area of 1 square meter is 1 lumen, its illuminance is 1 lux. Suppose the luminous flux on the facet dS is dΦ, then the illuminance E on this facet is: E=dΦ/dS.ġ lx=1 lm/㎡. The illumination/illuminance on a surface illuminated by light is defined as the luminous flux illuminating a unit area. It can be measured by an illuminance meter. The light intensity has a great influence on the photosynthesis of organisms. The international unit of luminosity is the candlelight accepted per square meter (called candela in Mainland China, Hong Kong and Macau). ![]() In photometry, “luminance” is the density of luminous intensity in a specified direction, but it is often misunderstood as illuminance. It is used to indicate the intensity of the light and the amount of the surface area of the object being illuminated. Referred to as illuminance, the unit is Lux or lx. ![]() Illumination intensity is a physical term that refers to the luminous flux of visible light received per unit area. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |