what is light power density
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- Lighting power density (LPD) is defined as the total amount of lighting power, in watts, provided to a given floor area, in square feet. A conventional general office lighting design has an LPD around 1.2 W/ft2, while an optimized design can be 0.8 W/ft2 or below.
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- Pixel density - The pixel density of a display represents the number of pixels over an area of one inch. It’s measured in “pixels per inch”, or ppi. The higher the number, the more detailed and good-looking the display is.
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- The term optical density is normally, but not always, understood to be the absolute value of the logarithm with base 10 of the power transmission factor of an optical attenuator: For example, an optical density of 3 means that the optical power is attenuated by the factor 103 = 1000. That would correspond to an attenuation by 30 decibels. If several attenuators are used in series, their optical densities can simply be added. The optical density is often said to be identical with the absorbance.
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- Pixel density: Pixel density - The pixel density of a display represents the number of pixels over an area of one inch. It’s measured in “pixels per inch”, or ppi. The higher the number, the more detailed and good-looking the display is.
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- Energy density is the amount of energy or calories in a. particular weight of food and is generally presented as. the number of calories in a gram (kcal/g). Foods with a. lower energy density provide fewer calories per gram than. foods with a higher energy density. For the same amount.
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The Low Pressure Sodium Lamp Figure S2 shows the energy balance of a typical low pressure sodium lamp, which reveals that in fact only about 30% of the input power is converted into visible light. This percentage is comparable with other modern discharge lamps.
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Fission and Fusion Energy density of various fuel sources. The amount of energy released in nuclear reactions is astounding. Table 1 shows how long a 100 Watt light bulb could run from using 1 kg of various fuels. The natural uranium undergoes nuclear fission and thus attains very high energy density (energy stored in a unit of mass).
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- Watts are a measure of power, not brightness. A 15W fluorescent bulb can be as bright as a 60W incandescent bulb, since fluorescent bulbs are more efficient. LED light bulbs are even more efficient, and can produce the same brightness for less than 8 watts of power. Do not believe the myth that leaving fluorescent lights on saves money.
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Candlepower Compared to Lumens Multiply candela by 12.57 to convert to lumens. For example, the 20 watt lamp used in the SL-35X is rated at 450 lumens or 35.8 Mean Spherical Candela. Peak Beam Intensity (Candlepower) is a measure of the brightest spot in the focused beam.
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Flashlight Applications and Beam Patterns High Performance, High Lumen (HPL): A good choice for down-range applications requiring optimal beam distance, as these flashlights throw light a long distance and feature an enhanced lumen output. Performance Characteristics.
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Power density This article is about power per volume. For power per area, see surface power density. Power density (or volume power density or volume specific power) is the amount of power (time rate of energy transfer) per unit volume. In energy transformers including batteries, fuel cells, motors, etc., and also power supply units or similar, power density refers to a volume.
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Density Matrix (5). In general, this density matrix describes a mixed state, for example, a beam of unpolarized electrons or the photons emitted from an incoherent source such as an incandescent lamp. The pure state is a special case of the mixed state when all members of the ensemble are in the same state.See Statistical mechanics. (4).5). In general, this density matrix describes a mixed state, for example, a beam of unpolarized electrons or the photons emitted from an incoherent source such as an incandescent lamp. The pure state is a special case of the mixed state when all members of the ensemble are in the same state. See Statistical mechanics.
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Learn About Brightness Learn About Brightness. Brightness is a description of light output, which is measured in lumens (not watts). Light bulb manufacturers include this information and the equivalent standard wattage right on the packaging. Common terms are soft white 60, warm light 60, and 60 watt replacement..
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Luminous efficacy Lighting efficiency. Artificial light sources are usually evaluated in terms of luminous efficacy of the source, also sometimes called wall-plug efficacy. This is the ratio between the total luminous flux emitted by a device and the total amount of input power (electrical, etc.) it consumes.
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Universe The present overall density of the Universe is very low, roughly 9.9 × 10−30 grams per cubic centimetre. This mass-energy appears to consist of 73% dark energy, 23% cold dark matter and 4% ordinary matter. The density of atoms is about a single hydrogen atom for every four cubic meters of volume. The properties of dark energy and dark matter are not known. Dark matter slows the expansion of the Universe.
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Light Pollution: Meaning, Causes, Effects, Solutions Light pollution is referred to as 'pollution' because it adversely affects the night sky, contaminating the darkness with light. Light pollution refers to the way that electric lights, street lamps and so on leave cities brightly lit right round the clock. Any kind of light can cause light pollution, but electric lights and sodium vapor lamps are the most common. Causes of light pollution. 1. Electricity.
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Candlepower Candlepower (abbreviated as cp) is an obsolete unit expressing luminous intensity, equal to 0.981 candelas.
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- Define charge density. charge density synonyms, charge density pronunciation, charge density translation, English dictionary definition of charge density. n. The electric charge per unit area or per unit volume of a body or of a region of space. n the electric charge per unit volume of a medium or body or per...
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Energy density For energy per unit mass or energy density of foods, see specific energy. Energy density is the amount of energy stored in a given system or region of space per unit volume. Colloquially it may also be used for energy per unit mass, though the accurate term for this is specific energy.
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What today's consumers need to know about lumens A candlepower. as a unit of measure is not the same as a foot-candle. A candlepower. is a measurement of the light at the source, not at the object you light up. And a candela is the metric equivalent of the light output of that one candle, based on metric calculations.
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- Power Factor is the ratio of watts to Root Mean Square (RMS) Volt-Amperes of the ballast. High power factor ballasts (power factor above 0.90) draw less current than low power factor. ballasts rated for the same wattage lamps.
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astronomy The intensity of cosmic microwave The average density of matter within it. Measurement of the sizes of hot spots in the temperature distribution of the cosmic microwave background suggests that the universe is flat. Yet, the combined density of all the matter and energy we see, plus the dark matter we infer, is only about a quarter of the critical density.
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- Lumens to watts calculation formula. The power P in watts (W) is equal to the luminous flux φ V in lumens (lm), divided by the luminous efficacy η in lumens per watt (lm/W): P (W) = φ V(lm) / η (lm/W). So.
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Solar panel Currently the best achieved sunlight conversion rate (solar module efficiency) is around 21.5% in new commercial products typically lower than the efficiencies of their cells in isolation. The most efficient mass-produced solar modules have power density values of up to 175 W/m2 (16.22 W/ft2).
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All You Need To Understand About Energy-Efficient Home Lighting: Watts vs. Lumens Watts measure the amount of electrical power used to light a bulb. Essentially, by that definition it means that the more watts a bulb show the more power it will consume to produce light. So a 200 watt bulb will use more power than a 100 watt bulb, giving just a little bit better and brighter light.
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Optical Density and Light Speed Optical Density and the Index of Refraction Like any wave, the speed of a light wave is dependent upon the properties of the medium. In the case of an electromagnetic wave, the speed of the wave depends upon the optical density of that material.