0
1 answer
A steradian is the solid angle subtended at the centre of a sphere by radius r by a portion of the surface of the sphere which has area r2.
1 answer
None. A radian is a measure of angular separation in 1-dimensional space, a steradian is a measure in 2-dimensional space. It makes no sense to try to convert from one to the other.
1 answer
None. A degree is a measure of angular separation in 1-dimensional space, a steradian is a measure in 2-dimensional space. It makes no sense to try to convert from one to the other.
1 answer
nopes.
radian is the ratio between the length of an arc and its radius.
A steradian can be defined as the solid angle subtended at the center of a unit sphere by a unit area on its surface. For a general sphere of radius r, any portion of its surface with area A = r2 subtends one steradian.
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None. A degree is a measure of angular separation in 1-dimensional space, a steradian is a measure in 2-dimensional space. It makes no sense to try to convert from one to the other.
1 answer
There is no direct ratio between radians and steradians since they measure different things. Radians measure angles in a two-dimensional plane, while steradians measure solid angles in three-dimensional space. However, both units are related by the formula: 1 steradian = (4π/1) square radians.
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The supplementary units are the radian and steradian units. This SI classification was made in 1995 but was later abandoned and the units were regrouped as derived units.
3 answers
You can however convert candlepower to lumen/steradian.
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Candela is the current SI unit of luminous intensity, which is equal to 1/683 Watts per steradian with a frequency of 540 THz (lime colour as a specific fequency corresponds to a specific colour of light). A watt is 1 joule of energy per second, a steradian is the 3D equivalent of a radian.
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You do not convert. STERADIAN is a two dimensioal measurement RADIAN is a one dimensional measurement.
Just as you cannot convert area into degrees (of angular measurement)
1 answer
if alpha is the solid angle subtended by a cone and theta is the 2d projection angle of this solid angle...Then----(both alpha and theta are in radians then)
cos(theta) = 1 - (alpha/2*pi)
1 answer
The SI unit for measuring solid angles is a steradian : the stereo version of the 2-dimensional unit, the radian. The maximum value of a 3-d angle is 4*pi steradians which is approx equal to 41253 degrees.
1 answer
Length - metre - m
Mass - kilogram - kg
Temperature - kelvin - K
Time - second - s
Amount of substance - mole - mol
Electric current - ampere - A
Luminous intensity - candela - cd
Plane angles - radian - rad
Solid angle - steradian - sr
1 answer
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 3 words with the pattern -T--A--A-. That is, nine letter words with 2nd letter T and 5th letter A and 8th letter A. In alphabetical order, they are:
ataraxias
steradian
stomachal
1 answer
1 lumen = 1 candela per steradian.
1 candela = 1/683 watts per steradians (assuming 540nm light wavelength).
Assuming that the light is collected from a single steradian:
1 Lumen = 1 Candela -> = 1/683 Watt -> Watt = 683 Lumens
1 Joule = 1 Watt per Second -> Watt = Joule/Second
Hence:
683 Lumen = 1 Joule/Second
Under the above assumptions1 Lumen = 1/683 Joule/Second3 answers
Particle displacement is a measurement of distance of the movement of a particle in a medium as it transmits a wave. Distance is measured in meters.
6 answers
Supplementary units in the SI system are used to measure solid angles and angles. The supplementary unit for solid angles is the steradian (symbol: sr), which measures how much of the space a three-dimensional object occupies. The supplementary unit for angles is the radian (symbol: rad), which measures the angle subtended by an arc of a circle that is equal in length to the radius of the circle.
3 answers
The SI units of measure are any of the units adopted for international use under the " Système International d'Unités (SI)", now employed for all scientific and most technical purposes.
There are seven fundamental units: the metre, kilogram, second, ampere, Kelvin, candela, and mole; and two supplementary units: the radian and the steradian. All other units are derived by multiplication or division of these units without the use of numerical factors
1 answer
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 6 words with the pattern S-ER--I--. That is, nine letter words with 1st letter S and 3rd letter E and 4th letter R and 7th letter I. In alphabetical order, they are:
sherifian
steradian
stereoing
sterilise
sterility
sterilize
1 answer
antipodean, Crimean, Judaean, Korean,Albion,Gambian, Zambian,lesbian,Arabian, Bessarabian, Fabian, gabion, Sabian, Swabian,amphibian, Libyan, Namibian,Sorbian,Danubian, Nubian,Colombian , Serbian , Nietzschean,Chadian, Trinidadian,Andean, Kandyan,guardian,Acadian, Akkadian, Arcadian, Barbadian, Canadian, circadian, Grenadian, Hadean, Orcadian, Palladian, radian, steradian,Archimedean, comedian, epicedian, median, tragedian,ascidian, Derridean, and Dravidian
2 answers
A candela is the power emitted by a source of light in a set direction with a correction to account for the different sensitivity of the human eye to different wavelengths of light.
One candela is defined as the luminous intensity of a light source emitting light in one direction at a frequency of 540 x 1012 hertz and has a radiant intensity in that direction of 1/683 watts per steradian.
3 answers
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 17 words with the pattern -----D-AN. That is, nine letter words with 6th letter D and 8th letter A and 9th letter N. In alphabetical order, they are:
acaridean
acaridian
circadian
custodian
cystidean
desmidian
epicedian
euclidean
euclidian
floridean
groundman
jaspidean
prosodian
quotidian
rachidian
steradian
tragedian
1 answer
There is not an extensive amount of laser tag system brands; therefore, those that do exist are either extremely high quality or not worth your time at all. Some of the high quality names of laser tag systems include LaserMaxx, Zone Laser Tag, and Steradian Technologies. You can visit each of their websites to find out more information on their products and services.
2 answers
Not directly, as you are comparing apples with oranges in two senses: (a) a lumen is an SI unit, whereas a candlepower is an Imperial unit, and (b) lumens are used to measure luminous flux, whereas candlepower is used to measure luminous intensity.
2 answers
candela
--------------------------------------------
The official international definition of candela (1979) is:
"The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 10e12 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian".
9 answers
a 100W incandescent lamp emits 120 candela.
lumen is the unit for luminous intensity per steradian ,an lamp emits in all direction
therefore a 16.25watt lamp contains 19.5 lumen
Answer
The lumen is the SI unit for luminous flux -which describes the output power of visible light expressed in photometric units. The ratio of a lamp's output luminous flux to its input power is termed 'efficacy', expressed in lumens per watt. The efficacy for incandescent lamp varies from 5-15 lumens per watt. So the output of a 16.25-W incandescent lamp will be between 80-245 W.
2 answers
A watt is a unit of power; candlepower is measured in candelas (sometimes called candles), and is a unit of luminous intensity. A candela is a lumen per steradian. A lumen is a unit of luminous flux, which is radiant power tempered by the response of the human eye. Thus, one watt of radiant power at the wavelength of peak response of the eye for bright light (about 555 nanometer) equals 683 lumen. That's green light; light of other colors will equal less.
A steradian is a unit of solid angle; there are 4*pi steradians in a sphere. So clearly, we cannot convert watts to candlepower, just as we can't convert pounds to inches. But we CAN convert if we make a few assumptions. Candlepower depends on the direction from the light source. For a given light source, reflectors and lenses will greatly affect the numbers. So let's assume an isotropic source (one that radiates equally in all directions). One candlepower would then equal 4*pi lumen. If the wavelength of the light is 555 nm, then 4*pi/683 (or about 0.0184 watt) would be the equivalent power. In the case of "white" light, that number would be about 0.14 or so (depending on the color temperature or "whiteness").
Please bear in mind that the power referred to above is the radiant power, not the power applied to the light source. In the case of incandescent lamps, much applied power is converted to heat and infrared radiation.
3 answers
There are 7 basic units which are dimensionally independent and two supplementary units. These are:
Metre (length)
Kilogram (mass)
Second (time)
Ampere (electric current)
Kelvin (thermodynamic temperature)
Mole (amount of substance)
Candela (luminous intensity)
The two supplementary units are the radian and steradian which are measures of angles in 2 and 3 dimensional space (respectively).
Additionally, there are many other units that can be derived from these and basically, if anyone wants to measure a physical or chemical characteristic, there is probably a metric unit for it.
Examples:
Pascal, Joule, Watt, Newton, Tesla, Henry, Coulomb, Volt, Farad, Siemens, Weber, Ohm, Lux, Lumen, Becquerel, Gray, Sievert, Hertz, Katal.
1 answer
The International System of Units (SI) is the modern form of the metric system and comprises seven base units: meter for length, kilogram for mass, second for time, ampere for electric current, kelvin for temperature, mole for amount of substance, and candela for luminous intensity. Other units are derived from these base units.
3 answers
Light intensity refers to the amount of light energy that falls on a given surface area in a specific direction. It is typically measured in lux or lumens and is a key factor in determining the brightness of a light source.
9 answers
Surprise finding, spectacularly high counts from Rb XRF (X-ray fluorescent) source by M.A. Padmanabha Rao, PhD(AIIMS) led to six fundamental physics discoveries: Rb XRF source (Variable Energy X-ray source (AMC 2084, U.K.) showing 125,321 cps instead of the expected 4,400 Rb X-ray photon yield sec-1 0.5 steradian-1 triggered previously unexplored areas of research in X-ray Physics, Nuclear Physics, and Atomic Spectroscopy.
2 answers
It seems that some people consider these base units, some don't. You might want to make up your own mind about what you think about this point. However, I would go for "derived unit", simply because that's the official definition.
A radian is used to measure angles; the way it is defined is by dividing an arc on a circle by the radius; so naturally, the units are meters/meters. Or substitute any other unit of length for meter, such as angstrom/angstrom or AU/AU or light-years/light-years; but the result would be exactly the same. In other words, it's a dimensionless unit.
The same applies to the steradian, which is radian2. This, of course, is also a dimensionless unit. It is also officially considered a derived unit.
2 answers
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 83 words with the pattern ST-R-----. That is, nine letter words with 1st letter S and 2nd letter T and 4th letter R. In alphabetical order, they are:
staragens
starboard
starburst
starchers
starchier
starchily
starching
stardrift
stardusts
staretses
staretzes
starfruit
stargazed
stargazer
stargazes
staringly
starkened
starkness
starlight
starlings
starnoses
starostas
starriest
starrings
starshine
starships
starspots
starstone
startings
startlers
startling
startlish
starvings
starworts
steradian
stercoral
sterculia
stereoing
stereomes
sterigmas
sterilant
sterilely
sterilise
sterility
sterilize
sterlings
sternages
sternebra
sternfast
sternites
sternitic
sternmost
sternness
sternport
sternpost
sternsons
sternward
sternways
steroidal
stirabout
stirrable
stirrings
storables
storeroom
storeship
storewide
storiated
storiette
stormbird
stormiest
stormings
stormless
stormlike
stornelli
stornello
storybook
storyette
storyings
storyline
sturdiest
sturgeons
sturnuses
styrofoam
1 answer
The International System of Units (generally referred to as the "SI") is the system of units of measurement, based on the metric system adopted in France in 1791. The SI base units are:
- Length: metre/meter (m)
- Mass: kilogram (kg)
- Time: second (s)
- Electric current: ampere (A)
- Temperature: kelvin (K)
- Luminous intensity: candela (CD)
- Amount of substance: mole (mol)
All other units are derived from those seven. They include:
- Frequency: hertz (Hz)
- Angle: radian (rad)
- Force: newton (N)
- Pressure: pascal (Pa)
- Energy: joule (J)
- Power: watt (W)
- Electric potential: volt (V)
- Electric charge: coulomb (C)
- Capacitance: farad (F)
- Inductance: Henry (H)
- Resistance: ohm (Ω)
- Magnetic flux: weber (Wb)
- Magnetic field strength: tesla (T)
- Electric conductance: siemens (S)
- Solid angle: steradian (sr)
- Temperature: Celsius (°C)
- Luminous flux: lumen (lm)
- Illuminance: lux (lx)
- Radioactivity: becquerel (Bq)
- Adsorbed dose of ionizing radiation: gray (Gy)
- Equivalent dose of ionizing radiation: sievert (SV)
- Catalytic activity: katal (kat)
1 answer
Luminous intensity is measured in Candelas.
If a light source emits one candela of luminous intensity uniformly across a solid angle of one steradian, its total luminous flux emitted into that angle is one lumen. Alternatively, an isotropic one-candela light source emits a total luminous flux of exactly 4π lumens. The lumen can be thought of casually as a measure of the total "amount" of visible light in some defined beam or angle, or emitted from some source. A standard North American 100 watt incandescent light bulb emits 1500-1700 lumens,[1] while a standard European 230 V model emits 1200-1400 lm.[2] A 100 watt high-pressure sodium vapor lamp emits around 15,000 lumens.[3] The number of lumens produced per watt of power consumed is the wall-plug luminous efficacy of the source.
4 answers
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 102 words with the pattern S--R--I--. That is, nine letter words with 1st letter S and 4th letter R and 7th letter I. In alphabetical order, they are:
sacralise
sacralize
sacrarial
sacrarium
sacrifice
sacrifide
sacrified
sacrifies
safranine
safranins
sapremias
saprobial
saprolite
sarrasins
sarrazins
satrapies
scarfpins
scarfwise
scarified
scarifier
scarifies
scarpaing
scarphing
scorching
scoreline
scorified
scorifier
scorifies
scorodite
scurrying
searching
searobins
secrecies
secreting
secretins
secretion
secretive
serranids
serrating
serration
serrefile
sharifian
sharklike
sherifian
shorebird
shoreline
shoreside
shortlist
skirtlike
skurrying
slurrying
smirching
snirtling
sopranini
sopranino
sopranist
sorrowing
spareribs
sparklier
sparklies
sparkling
sparteine
spiraling
spiralism
spiralist
spirality
spiration
spirewise
spiriting
spiritism
spiritist
spirulina
sporicide
sporidial
sporidium
starchier
starchily
starching
stardrift
starshine
starships
startling
startlish
steradian
stereoing
sterilise
sterility
sterilize
storewide
stormbird
stormlike
storyline
subregion
sunrising
supremity
swarajism
swarajist
swarthier
swarthily
swordbill
swordfish
swordlike
1 answer
1000m 10n Prefix Symbol
10008 1024 yotta Y
10007 1021 zetta Z
10006 1018 exa E
10005 1015 peta P
10004 1012 tera T
10003 109 giga G
10002 106 mega M
10001 103 kilo k
10002⁄3 102 hecto h
10001⁄3 101 deca da
10000 100 (none) (none)
1000−1⁄3 10−1 deci d
1000−2⁄3 10−2 centi c
1000−1 10−3 milli m
1000−2 10−6 micro µ
1000−3 10−9 nano n
1000−4 10−12 pico p
1000−5 10−15 femto f
1000−6 10−18 atto a
1000−7 10−21 zepto z
1000−8 10−24 yocto y
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Radiance is the variable directly measured by remote sensing instruments. Basically, you can think of radiance as how much light the instrument "sees" from the object being observed. When looking through an atmosphere, some light scattered by the atmosphere will be seen by the instrument and included in the observed radiance of the target. An atmosphere will also absorb light, which will decrease the observed radiance. Radiance has units of watt/steradian/square meter. Reflectance is the ratio of the amount of light leaving a target to the amount of light striking the target. It has no units. If all of the light leaving the target is intercepted for the measurement of reflectance, the result is called "hemispherical reflectance." Reflectance (or more specifically hemispherical reflectance) is a property of the material being observed. Radiance, on the other hand, depends on the illumination (both its intensity and direction), the orientation and position of the target and the path of the light through the atmosphere. With effort, many of the atmospheric effects and the solar illumination can be compensated for in digital remote sensing data. This yields something which is called "apparent reflectance," and it differs from true reflectance in that shadows and directional effects on reflectance have not been dealt with. Many people refer to this (rather inaccurately) as "reflectance." For most of the vegetation indices in this FAQ, radiance, reflectance, and apparent reflectance can be used interchangeably. However, since reflectance is a property of the target material itself, you will get the most reliable (and repeatable) vegetation index values using reflectance. Apparent reflectance is adequate in many cases. See the related link.
2 answers
SI stands for theInternational System of Units. They are called "SI" units because in French, International System of Units is written Système International d'Unités.
SI Base Units
- Length: meter (metre, m)
- Mass: kilogram (kg)
- Time: second (s)
- Electric current: ampere (A)
- Thermodynamic temperature: Kelvin (K)
- Amount of substance: mole (mol)
- Luminous intensity: candela (CD)
Some Derived SI Units :-The name of the unit and its symbol(s) is listed for each.
- Area: square meter (m2)
- Volume: cubic meter (m3) and liter (litre, L) (1 m3 = 1000 L)
- Frequency: Hertz (Hz, s-1)
- Density: kilogram per cubic meter (kg/m3) or gram per mL (g/mL) (1000 kg/m3 = 1 g/mL)
- Velocity or Speed: meter per second (m/s)
- Angular Velocity: radian per second (rad/s)
- Angular Displacement: radian (rad)
- Acceleration: meter per second per second (m/s2)
- Force: newton (N, kg .m/s2)
- Torque:newton meter (Nm)
- Pressure: pascal (P, N/m2)
- Work, Energy, Heat: joule (J, N . m)
- Power: watt (W, J/s)
- Electric Charge: coulomb (C, A . s)
- Potential difference: volt (V, W/A, J/C)
- Electric Field: volt per meter or newton per coulomb (V/m, N/C)
- Electric Resistance: ohm (Greek letter Omega, V/A)
- Electrical conductivity: siemen (S, 1/R)
- Capacitance: farad (F, A .s/V)
- Magnetic Flux: weber (Wb, V .s)
- Inductance: Henry (H, W .s/A)
- Magnetic Flux Density: tesla (T, Wb/m2)
- Magnetic Field Strength: ampere per meter (A/m)
- Entropy: joule per kelvin (J/K)
- Specific Heat: joule per kilogram kelvin (J/(kg . K))
- Thermal Conductivity: watt per meter kelvin (W/(m . K))
- Radiant Intensity: watt per steradian (W/sr)
*Use the related Links below this answer to get more information about SI units, including prefixes and other related units.
4 answers
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 177 words with the pattern ---RA-I--. That is, nine letter words with 4th letter R and 5th letter A and 7th letter I. In alphabetical order, they are:
adoration
affraying
aggracing
aggrading
aggrating
amoralism
amoralist
amorality
andradite
ashramite
ataraxias
ataraxics
ataraxies
averaging
barraging
bedraping
betraying
bewraying
characids
characins
cheralite
chirality
choralist
corrading
corrasion
corrasive
cybrarian
defraying
degrading
depraving
depravity
disrating
embracing
embracive
embraving
encraties
enframing
engracing
engraving
epurating
epuration
estradiol
estraying
evirating
exaration
exoration
extradite
extrality
fogramite
fogramity
forraying
gheraoing
gouramies
guaranies
hieracium
hieratica
hoorahing
hooraying
hurrahing
hurraying
hydracids
hydrating
hydration
hydrazide
hydrazine
intracity
iterating
iteration
iterative
latration
librarian
libraries
librating
libration
lucrative
migrating
migration
misrating
narrating
narration
narrative
neuration
nitramine
nitratine
nitrating
nitration
nonracial
operatics
operating
operation
operatise
operative
operatize
ostracise
ostracism
ostracize
outracing
outraging
outrating
outraving
overawing
perradial
perradius
petraries
pluralise
pluralism
pluralist
plurality
pluralize
prorating
proration
rebracing
recrating
redrawing
reframing
regrading
regrating
retracing
retrating
sacralise
sacralize
sacrarial
sacrarium
safranine
safranins
sarrasins
sarrazins
satrapies
serranids
serrating
serration
sopranini
sopranino
sopranist
spiraling
spiralism
spiralist
spirality
spiration
steradian
swarajism
swarajist
terracing
terrapins
terrarium
tetracids
tetradite
theralite
therapies
therapist
titrating
titration
triradial
ultrafine
ultrahigh
ultrarich
ultratiny
ultrawide
umbraging
umbratile
unbracing
unbraking
uncrating
undraping
undrawing
unpraying
untracing
upbraying
updrawing
upgrading
vibratile
vibrating
vibration
vibrative
warraning
warraying
zebrafish
1 answer
metre (m) for length kilogram (kg) for mass second (s) for time ampere (A) for electric current Kelvin (K) for thermodynamic temperature mole (mol) for amount of substance candela (cd) for luminous intensity
7 answers
SI stands for theInternational System of Units. They are called "SI" units because in French, International System of Units is written Système International d'Unités.
SI Base Units
- Length: meter (metre, m)
- Mass: kilogram (kg)
- Time: second (s)
- Electric current: ampere (A)
- Thermodynamic temperature: Kelvin (K)
- Amount of substance: mole (mol)
- Luminous intensity: candela (CD)
Some Derived SI Units :-The name of the unit and its symbol(s) is listed for each.
- Area: square meter (m2)
- Volume: cubic meter (m3) and liter (litre, L) (1 m3 = 1000 L)
- Frequency: Hertz (Hz, s-1)
- Density: kilogram per cubic meter (kg/m3) or gram per mL (g/mL) (1000 kg/m3 = 1 g/mL)
- Velocity or Speed: meter per second (m/s)
- Angular Velocity: radian per second (rad/s)
- Angular Displacement: radian (rad)
- Acceleration: meter per second per second (m/s2)
- Force: newton (N, kg .m/s2)
- Torque:newton meter (Nm)
- Pressure: pascal (P, N/m2)
- Work, Energy, Heat: joule (J, N . m)
- Power: watt (W, J/s)
- Electric Charge: coulomb (C, A . s)
- Potential difference: volt (V, W/A, J/C)
- Electric Field: volt per meter or newton per coulomb (V/m, N/C)
- Electric Resistance: ohm (Greek letter Omega, V/A)
- Electrical conductivity: siemen (S, 1/R)
- Capacitance: farad (F, A .s/V)
- Magnetic Flux: weber (Wb, V .s)
- Inductance: Henry (H, W .s/A)
- Magnetic Flux Density: tesla (T, Wb/m2)
- Magnetic Field Strength: ampere per meter (A/m)
- Entropy: joule per kelvin (J/K)
- Specific Heat: joule per kilogram kelvin (J/(kg . K))
- Thermal Conductivity: watt per meter kelvin (W/(m . K))
- Radiant Intensity: watt per steradian (W/sr)
*Use the related Links below this answer to get more information about SI units, including prefixes and other related units.
1 answer
Radiation is emitted from something and travels from its point of origin to somewhere else.
When radiation hits something else (and is therefore stopped) the thing that has been hit is said to have been irradiated.
Thus a sunbather is undergoing irradiation by radiation emitted by the sun.
7 answers
The sum of these little guys, photons covering all frequencies and covering all the earth (without being reflected or scattered off) is a really, really, really big number. Even over a short period of time. (And the answer would have to be averaged for a number of reasons.) Something like 2 x 10really big number per day would be close.
9 answers
Reference from encyclopedia.com:
Olympian:
•antipodean, Crimean, Judaean, Korean •Albion •Gambian, Zambian •lesbian •Arabian, Bessarabian, Fabian, gabion, Sabian, Swabian •amphibian, Libyan, Namibian •Sorbian •Danubian, Nubian •Colombian • Serbian • Nietzschean •Chadian, Trinidadian •Andean, Kandyan •guardian •Acadian, Akkadian, Arcadian, Barbadian, Canadian, circadian, Grenadian, Hadean, Orcadian, Palladian, radian, steradian •Archimedean, comedian, epicedian, median, tragedian •ascidian, Derridean, Dravidian, enchiridion, Euclidean, Floridian, Gideon, Lydian, meridian, Numidian, obsidian, Pisidian, quotidian, viridian •Amerindian, Indian •accordion, Edwardian •Cambodian, collodion, custodian, melodeon, nickelodeon, Odeon •Freudian • Bermudian • Burundian •Burgundian •Falstaffian, Halafian •Christadelphian, Delphian, Philadelphian •nymphean • ruffian • Brobdingnagian •Carolingian • Swedenborgian •logion, Muskogean •Jungian •magian, Pelagian •collegian •callipygian, Cantabrigian, Phrygian, Stygian •Merovingian • philologian • Fujian •Czechoslovakian • Pickwickian •Algonquian • Chomskian •Kentuckian •battalion, galleon, medallion, rapscallion, scallion •Anglian, ganglion •Heraklion •Dalian, Malian, Somalian •Chellean, Machiavellian, Orwellian, Sabellian, Trevelyan, triskelion •Wesleyan •alien, Australian, bacchanalian, Castalian, Deucalion, episcopalian, Hegelian, madrigalian, mammalian, Pygmalion, Salian, saturnalian, sesquipedalian, tatterdemalion, Thessalian, Westphalian •anthelion, Aristotelian, Aurelian, carnelian, chameleon, Karelian, Mendelian, Mephistophelian, Pelion, Sahelian •Abbevillian, Azilian, Brazilian, caecilian, Castilian, Chilean, Churchillian, civilian, cotillion, crocodilian, epyllion, Gillian, Lilian, Maximilian, Pamphylian, pavilion, postilion, Quintilian, reptilian, Sicilian, Tamilian, vaudevillian, vermilion, Virgilian •Aeolian, Anatolian, Eolian, Jolyon, Mongolian, napoleon, simoleon •Acheulian, Boolean, cerulean, Friulian, Julian, Julien •bullion •mullion, scullion, Tertullian •Liverpudlian •Bahamian, Bamian, Damian, Mesopotamian, Samian •anthemion, Bohemian •Endymion, prosimian, Simeon, simian •isthmian • antinomian •Permian, vermian •Oceanian •Albanian, Azanian, Iranian, Jordanian, Lithuanian, Mauritanian, Mediterranean, Panamanian, Pennsylvanian, Pomeranian, Romanian, Ruritanian, Sassanian, subterranean, Tasmanian, Transylvanian, Tripolitanian, Turanian, Ukrainian, Vulcanian •Armenian, Athenian, Fenian, Magdalenian, Mycenaean (US Mycenean), Slovenian, Tyrrhenian •Argentinian, Arminian, Augustinian, Carthaginian, Darwinian, dominion, Guinean, Justinian, Ninian, Palestinian, Sardinian, Virginian •epilimnion, hypolimnion •Bosnian •Bornean, Californian, Capricornian •Aberdonian, Amazonian, Apollonian, Babylonian, Baconian, Bostonian, Caledonian, Catalonian, Chalcedonian, Ciceronian, Devonian, draconian, Estonian, Etonian, gorgonian, Ionian, Johnsonian, Laconian, Macedonian, Miltonian, Newtonian, Oregonian, Oxonian, Patagonian, Plutonian, Tennysonian, Tobagonian, Washingtonian •Cameroonian, communion, Mancunian, Neptunian, Réunion, union •Hibernian, Saturnian •Campion, champion, Grampian, rampion, tampion •thespian • Mississippian • Olympian •Crispian •Scorpian, scorpion •cornucopian, dystopian, Ethiopian, Salopian, subtopian, Utopian •Guadeloupian •Carian, carrion, clarion, Marian •Calabrian, Cantabrian •Cambrian • Bactrian •Lancastrian, Zoroastrian •Alexandrian • Maharashtrian •equestrian, pedestrian •agrarian, antiquarian, apiarian, Aquarian, Arian, Aryan, authoritarian, barbarian, Bavarian, Bulgarian, Caesarean (USCesarean), centenarian, communitarian, contrarian, Darien, disciplinarian, egalitarian, equalitarian, establishmentarian, fruitarian, Gibraltarian, grammarian, Hanoverian, humanitarian, Hungarian, latitudinarian, libertarian, librarian, majoritarian, millenarian, necessarian, necessitarian, nonagenarian, octogenarian, ovarian, Parian, parliamentarian, planarian, predestinarian, prelapsarian, proletarian, quadragenarian, quinquagenarian, quodlibetarian, Rastafarian, riparian, rosarian, Rotarian, sabbatarian, Sagittarian, sanitarian, Sauveterrian, sectarian, seminarian, septuagenarian, sexagenarian, topiarian, totalitarian, Trinitarian, ubiquitarian, Unitarian, utilitarian, valetudinarian, vegetarian, veterinarian, vulgarian •Adrian, Hadrian •Assyrian, Illyrian, Syrian, Tyrian •morion • Austrian •Dorian, Ecuadorean, historian, Hyperborean, Nestorian, oratorian, praetorian (US pretorian), salutatorian, Salvadorean, Singaporean, stentorian, Taurean, valedictorian, Victorian •Ugrian • Zarathustrian •Cumbrian, Northumbrian, Umbrian •Algerian, Cancerian, Chaucerian, Cimmerian, criterion, Hesperian, Hitlerian, Hyperion, Iberian, Liberian, Nigerian, Presbyterian, Shakespearean, Siberian, Spenserian, Sumerian, valerian, Wagnerian, Zairean •Arthurian, Ben-Gurion, centurion, durian, holothurian, Khachaturian, Ligurian, Missourian, Silurian, tellurian •Circassian, Parnassian •halcyon • Capsian • Hessian •Albigensian, Waldensian •Dacian • Keatsian •Cilician, Galician, Lycian, Mysian, Odyssean •Leibnizian • Piscean • Ossian •Gaussian • Joycean • Andalusian •Mercian • Appalachian • Decian •Ordovician, Priscian •Lucian •himation, Montserratian •Atlantean, Dantean, Kantian •bastion, Erastian, Sebastian •Mozartian • Brechtian • Thyestean •Fortean • Faustian • protean •Djiboutian •fustian, Procrustean •Gilbertian, Goethean, nemertean •pantheon •Hogarthian, Parthian •Lethean, Promethean •Pythian • Corinthian • Scythian •Lothian, Midlothian •Latvian • Yugoslavian •avian, Batavian, Flavian, Moldavian, Moravian, Octavian, Scandinavian, Shavian •Bolivian, Maldivian, oblivion, Vivian •Chekhovian, Harrovian, Jovian, Pavlovian •alluvion, antediluvian, diluvian, Peruvian •Servian • Malawian • Zimbabwean •Abkhazian • Dickensian •Caucasian, Malaysian, Rabelaisian •Keynesian •Belizean, Cartesian, Indonesian, Milesian, Salesian, Silesian •Elysian, Frisian, Parisian, Tunisian •Holmesian •Carthusian, Malthusian, Venusian
2 answers
Reflection is the process by which electromagnetic radiation is returned either at the boundary between two media (surface reflection) or at the interior of a medium (volume reflection), whereas transmission is the passage of electromagnetic radiation through a medium. Both processes can be accompanied by diffusion (also called scattering), which is the process of deflecting a unidirectional beam into many directions. In this case, we speak about diffuse reflection and diffuse transmission (Fig. II.14). When no diffusion occurs, reflection or transmission of an unidirectional beam results in an unidirectional beam according to the laws of geometrical optics (Fig. II.15). In this case, we speak about regular reflection (or specular reflection) and regular transmission(or direct transmission). Reflection, transmission and scattering leave the frequency of the radiation unchanged. Exception: The Doppler effect causes a change in frequency when the reflecting material or surface is in motion.
Absorptionis the transformation of radiant power to another type of energy, usually heat, by interaction with matter.
Fig. II.14 - a-c: Direct, mixed and diffuse reflection d-f: direct, mixed and diffuse transmission
Fig. II.15 - When directly reflected or directly transmitted, an unidirectional beam follows the laws of geometrical optics: direct reflection (left): ain = aout, direct transmission (right): n1 · sin(ain) = n2 · sin(aout) with n1 and n2 denoting the respective medium´s index of refraction
II.8.a. Reflectance r, Transmittance t, and Absorptancea
In general, reflection, transmission and absorption depend on the wavelength of the affected radiation. Thus, these three processes can either be quantified for monochromatic radiation (in this case, the adjective "spectral" is added to the respective quantity) or for a certain kind of polychromatic radiation. For the latter, the spectral distribution of the incident radiation has to be specified. In addition, reflectance, transmittance and absorptance might also depend on polarization and geometric distribution of the incident radiation, which therefore also have to be specified.Thereflectance r is defined by the ratio of reflected radiant power to incident radiant power. For a certain area element dA of the reflecting surface, the (differential) incident radiant power is given by the surface's irradiance Ee, multiplied with the size of the surface element, thus
dFe,incident = Ee dA
and the (differential) reflected radiant power is given by the exitance Me, multiplied with the size of the surface element:
dFe,reflected = Me dA
Thus,
or
Me = r Ee
Total reflectance is further subdivided in regular reflectance rr and diffuse reflectancerd, which are given by the ratios of regularly (or specularly) reflected radiant power and diffusely reflected radiant power to incident radiant power. From this definition, it is obvious that
r = rr + rd
The transmittance t of a medium is defined by the ratio of transmitted radiant power to incident radiant power. Total transmittance is further subdivided in regular transmittance tr and diffuse transmittance td, which are given by the ratios of regularly (or directly) transmitted radiant power and diffusely transmitted radiant power to incident radiant power.
Again,
t = tr + td
The absorptance a of a medium is defined by the ratio of absorbed radiant power to incident radiant power.
Being defined as ratios of radiant power values, reflectance, transmittance and absorptance are dimensionless.
Quantities such as reflectance and transmittance are used to describe the optical properties of materials. The quantities can apply to either complex radiation or to monochromatic radiation.
The optical properties of materials are not a constant since they are dependent on many parameters such as:
• thickness of the sample
• surface conditions
• angle of incidence
• temperature
• the spectral composition of the radiation (CIE standard illuminants A, B, C, D65 and other illuminants D)
• polarization effects
The measurement of optical properties of materials using integrating spheres is described in DIN 5036-3 and CIE 130-1998.
Descriptions of the principle measurements are presented in paragraph III.1.f below.
II.8.b. Radiance coefficient qe, Bidirectional reflectance distribution function (BRDF)
The radiance coefficient qe characterizes the directional distribution of diffusely reflected radiation. In detail, the radiance coefficient depends on the direction of the reflected beam and is defined by the ratio of the radiance reflected in this direction to the total incident irradiance. In general, the reflected radiance is not independent from the directional distribution of the incident radiation, which thus has to be specified.
In the USA, the concept of Bidirectional reflectance distribution function BRDF is similar to the radiance coefficient. The only difference is that the BRDF is a function of the directions of the incident and the reflected beam (Fig. ). In detail, the (differential) irradiance dEe impinging from a certain direction causes the reflected radiance dLe in another direction, which is given by
dLe = BRDF · dEe
This BRDF depends on more arguments than the radiance coefficient. However, its advantage is the simultaneous description of the material's reflection properties for all possible directional distributions of incident radiation, whereas the radiance coefficient generally is valid for just one specific directional distribution of incident radiation.
The unit of radiance coefficient and BRDF is 1/steradian. The BRDF is often abbreviated by the Greek letter ñ, which bears the danger of mixing the BRDF up with reflectance (see foregoing paragraph).
Fig. II.16 - Geometry used for the definition of the bidirectional reflectance distribution function (BRDF). The BRDF depends on the directions of incident and reflected radiation, which are given by the angles Ji and Jr, which are measured relative to the reflecting surface's normal, and the azimuth angles ji and jr, which are measured in the plane of the reflecting surface.
2 answers
librarian
magician
musician
christian
politician
electrician
mathematician
Hungarian
amphibian
Egyptian
disestablishmentarian
antidisestablishmentarianism
9 answers
