Astronomija

Razlika med svetilnostjo, svetlobnim tokom in sevalnim tokom?

Razlika med svetilnostjo, svetlobnim tokom in sevalnim tokom?


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To sem že poiskal in se spraševal o razlikah med njimi. Svetilnost je celotna energija, ki jo vir odda v vatih. Zmeden pa sem glede svetlobnega in sevalnega toka. Ker je sevalni tok skupna energija, ki jo oddaja predmet, ali bi to pomenilo, da je svetilnost enaka sevalnemu toku? Kako je potem svetlobni tok povezan s svetilnostjo? Ali je svetlobni tok le sevalni tok, ki pa prikazuje samo vidno svetlobo? In na tej spletni strani https://www.ifa.hawaii.edu/~barnes/ASTR110L_S03/inversesquare.html piše, da so lumni enota svetilnosti, kako pa, če so lumeni kandela krat steradijani?


Fotometrične enote so na prvi pogled pogosto videti zapletene.

Svetilnost

Svetilnost se nanaša na skupna energija, ki jo predmet sprosti na enoto časa. Ta količina je dimenzijsko enakovredna moči in se zato meri v džulih na sekundo ali v vatih $ ( mathrm {W}) $. Druga pogosta enota je sončna svetilnost $ mathrm {L} _ { odot} = 3,846 krat 10 ^ {26} $ $ mathrm {W} $.

Intenzivnost svetlobe

Intenzivnost svetlobe se nanaša na ponderirana na valovni dolžini moč, ki jo oddaja vir v določeno smer. Tu je pomembna tehtana valovna dolžina. Ker je človeško oko bolj občutljivo na nekatere valovne dolžine kot druge, je to utež zasnovano tako, da postavlja standard za zaznavanje. Ta znaša 555 $ $ mathrm {nm} $, valovna dolžina, na katero je človeško oko najbolj občutljivo. Ta enota se imenuje kandela $ ( mathrm {cd}) $ in je enakovredna viru, ki oddaja $ 555 $ $ mathrm {nm} $ z močjo $ frac {1} {683} $ $ mathrm {W} cdot mathrm {sr} ^ {- 1} $. V bistvu je to ob upoštevanju dejstva, da bo koncentracija enake količine svetlobe v manjši trdni kot videti videti svetlejša. Iskanje svetlobne jakosti vira z več valovnimi dolžinami je nekoliko bolj zapleteno. Določimo naslednje:

$ I_v $ je svetlobna jakost v kandelah,

$ I_e $ je jakost sevanja v vatih na steradian in

$ bar {y} ( lambda) $ je standardna funkcija svetilnosti, ki opravi tehtanje valovnih dolžin.

Nato lahko intenzivnost svetilnosti vira z več valovnimi dolžinami določimo tako:

$ I_v = 683 int_ {0} ^ { infty} bar {y} ( lambda) cdot frac {dI_e ( lambda)} {d lambda} d lambda $

Svetlobni tok

Svetlobni tok je enakovreden celotni valovni dolžini tehtani moči, ki jo oddaja vir. Podobno je svetilnosti. Izmerjen je v lumnu $ mathrm {lm} $, kar je enakovredno kandeli-steradianu $ ( mathrm {cd} cdot mathrm {sr}) $. To si lahko predstavljamo kot človeku koristno količino svetlobe, ki jo oddaja vir.

Radiometrične enote

Radiometrične enote so enake, le da se nanašajo na resnično oddajeno moč, brez ponderiranja valovnih dolžin.


V astronomiji svetilnost je točno tak, kot ste ga definirali.

V radiometrija, običajni izraz za to je sevalni tok. Torej, ja, gre za isto stvar.

Svetlobni tokpa je drugačno. To je izraz iz "fotometrije", ki je merjenje svetlobe *, kot jo zazna človeško oko "(dal sem jo v strašne narekovaje, ker v astronomijibeseda "fotometrija" običajno pomeni merjenje svetlobe brez kakršnega koli sklicevanja na človeško zaznavanje in se včasih ležerno uporablja za slikanje ali analizo slik). je analogno do svetilnosti / sevalnega toka, vendar ne isto, ker vključuje tehtanje energije svetlobe glede na to, kako dobro ali slabo jo človeško oko lahko zazna. (Za več podrobnosti glejte povezani članek na Wikipediji.)

Predstavljajte si radijski vir, ki ne oddaja vidne svetlobe. Astronom bi rekel, da ima svetilnost (recimo) $ X $ vatov. Z radiometričnega vidika ima sevalni tok popolnoma enake količine. Ampak bi imel svetlobni tok nič, saj človeško oko ne more zaznati radijskih fotonov.

to spletno mesto… pravi, da so lumni enota svetilnosti, kako pa, če so lumeni kandela krat steradijani?

Tehnično to spletno mesto v resnici ni pravilno, saj ležerno enači svetilnost (ali sevalni tok) s svetlobnim tokom.


Razmerje med Luxom, Lumenom in Wattom

Lux se uporablja za merjenje količine svetlobe na določenem območju & # 8211 en lux je enak enemu lumenu na kvadratni meter. Omogoča nam merjenje skupne & # 8220količine & # 8221 prisotne vidne svetlobe in intenzivnosti osvetlitve na površini. Tako je pomembno, v katero smer sveti vir svetlobe. Ta vrednost je ne glede na število svetlobnih virov, ki jih uporablja, barvo ali strukturo, kjer svetloba sije. Če je količina luksa označena s svetilko, je običajno v središču žarka, kjer je jakost svetlobe največja.

Lux je enota za merjenje svetlobe z upoštevanjem površine. Z drugimi besedami, jakost svetlobe.

Lux je odlična meritev za določanje, kaj vidimo kot svetlost žarka. Če je svetlobna moč koncentrirana na manjšem območju, to vidimo kot zelo svetlo. Če je svetlobna moč razpršena na večjem območju, to vidimo kot zelo šibko. Za nadzor svetlobne poti in ustvarjanje želenega vzorca žarka običajno uporabljamo ogledala, odsevnike in optiko. Lux določa tudi velikost jakosti svetlobe, ki potuje na razdalje. Luč, ki je konfigurirana za visoko luks, bo potovala dlje, vendar bo imela manjši odtis svetlobe, nizka luks pa bo nastavljena za potovanje na krajše razdalje, vendar bo imela večji odtis.


Svetlobni tok

Svetlobni tok (& # 934v) je energija na enoto časa (dQ / dt), ki jo seva vir iz vidnih valovnih dolžin. Natančneje, gre za energijo, ki seva v valovnih dolžinah, občutljivih na človeško oko, od približno 330 nm do 780 nm. Tako je svetlobni tok tehtano povprečje sevalnega toka v vidnem spektru. To je tehtano povprečje, ker se človeško oko ne odziva enako na vse vidne valovne dolžine.

Občutljivost očesa doseže vrh pri 555 nm in pade na približno 10 -4 pri 380 in 750 nm. To predstavlja obseg občutljivosti na dnevno svetlobo ali fotopičnega vida. Nočna občutljivost očesa, imenovana skotopični vid, se premakne proti modrem koncu vidnega, doseže vrh pri 507 nm in pade na 10 -4 pri 340 in 670 nm. Ta utežni faktor ali svetlobna učinkovitost (Vλ), omogoča pretvorbo sevalnega toka v svetlobni tok pri kateri koli valovni dolžini. V fotopičnem območju je vrhu pri 555 nm dodeljena pretvorbena vrednost 683 lumnov na vat. Lumen je enota svetlobnega toka in je opredeljena glede na kandelo, osnovno enoto SI, kot je meter ali sekunda. 1 lumen je opredeljen kot 1/4 & # 960 kandela, osnovna enota SI svetlobne intenzivnosti.

Ker oko ne vidi vseh valovnih dolžin enako dobro, je krivulja učinkovitosti zelo pomemben način za določanje svetlobnega toka iz vira. Najlažje je določiti svetlobni tok iz enobarvnega vira, ki proizvaja svetlobo na eni valovni dolžini.

Tako na primer nastane laserski kazalec 5 mW z valovno dolžino 680 nm

.005 W * .017 * 683 lm / W = .058 lm

Medtem ko proizvaja laserski kazalec 5 mW pri 630 nm

, 005 W * .265 * 683 lm / W =, 905 lm, bistveno večji svetlobni tok.

Določanje svetlobnega toka iz vira, ki seva čez spekter, je težje. Za določen vir je treba določiti spektralno porazdelitev moči. Ko je to končano, je treba izračunati svetlobni tok pri vsaki valovni dolžini ali v rednih intervalih za neprekinjene spektre. Če seštevamo tok na vsaki valovni dolžini, dobimo skupni tok, ki ga ustvari vir v vidnem spektru.

Z nekaterimi viri je to lažje narediti kot z drugimi. Standardna žarnica z žarilno nitko ustvarja neprekinjen spekter v vidnem polju in za določanje svetlobnega toka je treba uporabiti različne intervale. Za vire, kot je živosrebrna žarnica, pa je nekoliko lažje. Živo srebro oddaja svetlobo predvsem v linijskem spektru. Izžareva sevalni tok pri 6 primarnih valovnih dolžinah. Tako je lažje določiti svetlobni tok te svetilke v primerjavi z žarilno nitko.

Na splošno ni treba sami določiti svetlobnega toka. Običajno se daje za žarnico na podlagi laboratorijskih preskusov med izdelavo. Na primer, svetlobni tok za 100 W žarnico z žarilno nitko je približno 1700 lm. Te podatke lahko uporabimo za ekstrapolacijo na podobne sijalke. Tako je povprečna svetlobna učinkovitost žarnice z žarilno nitko približno 17 lm / W. Zdaj lahko to uporabimo kot približek za podobne žarnice z različnimi močmi. Proizvajalec v svojih podatkih za žarnico pogosto navede "začetne lumene". To je svetlobni tok za to svetilko. Navedena je na ta način, ker se s staranjem svetilke njena porazdelitev moči nekoliko spreminja in ne seva več natančno na valovnih dolžinah, kot je bila takrat, ko je bila nova. Za vse namene pa se za svetlobni tok lahko uporabijo „začetni lumni“ za kakršen koli potreben izračun.


Vsebina

Urejanje osvetlitve

Osvetljenost je merilo, koliko svetlobnega toka se razprostira na določenem območju. Svetlobni tok (merjen v lumnih) si lahko predstavljamo kot merilo celotne "količine" prisotne vidne svetlobe, osvetljenost pa kot merilo jakosti osvetlitve na površini. Dana količina svetlobe bo površino osvetlila bolj slabo, če se razprostira na večji površini, zato je osvetljenost obratno sorazmerna s površino, ko je svetlobni tok konstanten.

En luks je enak enemu lumnu na kvadratni meter:

Pretok 1000 lumnov, ki se enakomerno razprostira na površini 1 kvadratnega metra, osvetli kvadratni meter z osvetlitvijo 1000 luksov. Vendar enakih 1000 lumnov, razprostranjenih na 10 kvadratnih metrih, ustvari zatemnitev le 100 luksov.

Doseganje osvetlitve 500 luksov bi bilo mogoče v domači kuhinji z enim samim fluorescentnim svetilkom z izhodno močjo 12 000 lumnov. Za osvetlitev tovarniških tal z več desetkrat večjo površino kuhinje bi bilo treba na desetine takšnih naprav. Tako osvetlitev večje površine na enako raven luksov zahteva večje število lumnov.

Kot pri drugih enotah SI lahko tudi tukaj uporabite predpone SI, na primer kilolux (klx) je 1000 luksov.

Tu je nekaj primerov osvetljenosti pod različnimi pogoji:

Osvetljenost (lux) Površine, osvetljene z
0.0001 Brez lune, oblačno nočno nebo (zvezdna luč) [4]
0.002 Brezmesečno jasno nočno nebo s sijajem zraka [4]
0.05–0.3 Polna luna v jasni noči [5]
3.4 Temna meja civilnega mraka pod vedrim nebom [6]
20–50 Javne površine s temno okolico [7]
50 Družinske luči za dnevno sobo (Avstralija, 1998) [8]
80 Razsvetljava hodnika / stranišča poslovne stavbe [9] [10]
100 Zelo temen oblačen dan [4]
150 Peroni železniških postaj [11]
320–500 Pisarniška razsvetljava [8] [12] [13] [14]
400 Sončni vzhod ali sončni zahod na jasen dan.
1000 Oblačen dan [4] tipična osvetlitev TV studia
10,000–25,000 Celotna dnevna svetloba (ne neposredno sonce) [4]
32,000–100,000 Neposredna sončna svetloba

Osvetljenost svetlobnega vira na površini, pravokotni na smer do vira, je merilo jakosti tega vira, zaznanega s tega mesta. Na primer, zvezda navidezne magnitude 0 zagotavlja 2,08 mikroluksa (μlx) na površini Zemlje. [15] Komaj zaznavna zvezda magnitude 6 zagotavlja 8 nanoluksa (nlx). [16] Nezaščiteno Sonce zagotavlja osvetlitev do 100 kiloluksov (klx) na zemeljski površini, natančna vrednost je odvisna od letnega časa in atmosferskih razmer. Ta neposredna normalna osvetljenost je povezana s konstanto sončne osvetljenosti Esc, enako 128 000 luksov (glej Sončna svetloba in sončna konstanta).

Osvetljenost na površini je odvisna od tega, kako je površina nagnjena glede na vir. Na primer, žepna svetilka, usmerjena na steno, bo dala določeno stopnjo osvetlitve, če je usmerjena pravokotno na steno, če pa je svetilka namenjena povečevanju kotov na pravokotnik (pri ohranjanju enake razdalje), osvetljeno mesto postane večje in tako je manj močno osvetljena. Ko je površina nagnjena pod kotom do vira, se osvetljenost na površini zmanjša, ker nagnjena površina podre manjšemu trdnemu kotu od vira in zato prejme manj svetlobe. Pri točkovnem viru se osvetlitev na nagnjeni površini zmanjša za faktor, enak kosinusu kota med žarkom, ki prihaja iz vira, in normalno na površino. [17] Pri praktičnih problemih z osvetlitvijo lahko glede na informacije o načinu oddajanja svetlobe iz vsakega vira ter razdalji in geometriji osvetljenega območja numerično izračunamo osvetljenost na površini, tako da prispevamo prispevke vsake točke na vsaki Izvor svetlobe.

Razmerje med osvetljenostjo in obsevanjem Uredi

Kot vse fotometrične enote ima tudi luks ustrezno "radiometrično" enoto. Razlika med katero koli fotometrično enoto in njeno ustrezno radiometrično enoto je v tem, da radiometrične enote temeljijo na fizični moči, pri čemer se vse valovne dolžine enakomerno tehtajo, fotometrične enote pa upoštevajo dejstvo, da je vizualni sistem, ki tvori podobo človeškega očesa, bolj občutljiv na nekatere valovne dolžine kot druge, zato ima vsaka valovna dolžina drugačno težo. Utežni faktor je znan kot funkcija svetilnosti.

Luks je en lumen na kvadratni meter (lm / m 2), ustrezna radiometrična enota, ki meri obsev, pa je vat na kvadratni meter (W / m 2). Med luksi in W / m 2 ni nobenega pretvorbenega faktorja, za vsako valovno dolžino je različen pretvorbeni faktor in pretvorbe ni mogoče izvesti, če ne poznamo spektralne sestave svetlobe.

Vrhunec funkcije svetilnosti je pri 555 nm (zeleno), vidni sistem, ki tvori podobo očesa, je bolj občutljiv na svetlobo te valovne dolžine kot kateri koli drug. Za enobarvno svetlobo te valovne dolžine, količina osvetljenosti za določeno količino obsevanja je največja: 683,002 luksa na 1 W / m 2, obsev, potreben za 1 luks pri tej valovni dolžini, je približno 1,464 mW / m 2. Druge valovne dolžine vidne svetlobe ustvarjajo manj luksov na kvadrat kvadrata na meter. Funkcija svetilnosti pade na nič pri valovnih dolžinah zunaj vidnega spektra.

Za svetlobni vir z mešanimi valovnimi dolžinami lahko s pomočjo funkcije svetilnosti izračunamo število lumnov na vat. Da se svetlobni vir zdi razumno "bel", ne more biti sestavljen samo iz zelene svetlobe, na katero so vizualni fotoreceptorji, ki tvorijo oko, najbolj občutljivi, temveč mora vsebovati velikodušno mešanico rdečih in modrih valovnih dolžin, na katero je veliko manj občutljiv.

To pomeni, da beli (ali belkasti) svetlobni viri proizvedejo veliko manj lumnov na vat kot teoretični maksimum 683,002 lm / W. Razmerje med dejanskim številom lumnov na vat in teoretičnim maksimumom je izraženo kot odstotek, znan kot svetlobni izkoristek. Na primer, običajna žarnica z žarilno nitko ima svetlobni izkoristek le približno 2%.

V resnici se posamezne oči nekoliko razlikujejo po svojih funkcijah svetilnosti. Fotometrične enote pa so natančno določene in natančno merljive. Temeljijo na dogovorjeni standardni funkciji svetilnosti, ki temelji na meritvah spektralnih značilnosti oblikovanja slike vizualna fotorecepcija v mnogih posameznih človeških očeh.

Specifikacije za video kamere, kot so videokamere in nadzorne kamere, pogosto vključujejo minimalno stopnjo osvetljenosti v luksih, pri kateri bo kamera posnela zadovoljivo sliko. [ navedba potrebna ] Kamera z dobro zmogljivostjo pri šibki svetlobi bo imela nižjo oceno lux. Fotoaparati še vedno ne uporabljajo takšnih specifikacij, saj lahko daljše čase osvetlitve na splošno uporabimo za ustvarjanje slik pri zelo nizki stopnji osvetljenosti, v nasprotju s primerom pri video kamerah, kjer je največji čas osvetlitve običajno nastavljen s hitrostjo sličic.

Ustrezna enota v angleških in ameriških tradicionalnih enotah je sveča. Ena nožna sveča je približno 10,764 luksa. Ker je ena sveča svetilnost, ki jo na površino oddaja enkandela, ki je oddaljena eno nogo stran, bi lahko luks obravnavali kot "svečo meter", čeprav tega izraza odsvetujejo, ker ne ustreza standardom SI za imena enot.

En fot (ph) je enak 10 kiloluksom (10 klx).

En nox (nx) je enak 1 mililuksu (1 mlx).

V astronomiji je navidezna velikost merilo osvetljenosti zvezde v zemeljski atmosferi. Zvezda z navidezno magnitudo 0 je 2,54 mikroluksa zunaj zemeljske atmosfere in 82% tega (2,08 mikroluksa) pod jasnim nebom. [15] Zvezda z magnitudo 6 (ki je v dobrih pogojih komaj vidna) bi bila 8,3 nanoluksa. Običajna sveča (ena kandela), oddaljena kilometer, bi osvetlila 1 mikroluks - približno enako kot zvezda z magnitudo 1.

Unicode ima simbol za "lx": (㏓). To je stara koda za namestitev starih kodnih strani v nekaterih azijskih jezikih. Uporaba te kode ni priporočljiva.


Vsebina

26. generalna konferenca o utežih in merilih (CGPM) je ponovno določila fotometrične enote leta 2018. [1] Z novo definicijo, ki je začela veljati 20. maja 2019, je lumen

[. ] je opredeljeno z določitvijo številske vrednosti svetlobne učinkovitosti enobarvnega sevanja s frekvenco 540 × 10 12 Hz, Kcd, na 683, če je izraženo v enoti lm W –1 [. ]

Pred letom 2019 je opredelitev temeljila na kandeli. Lumen je povezan s kandelo kot

Polna krogla ima trden kot 4π steradianov, [2] zato ima svetlobni vir, ki enakomerno oddaja eno kandelo v vse smeri, skupni svetlobni tok 1 cd × 4π sr = 4π cd⋅sr ≈ 12,57 lumnov. [3]

Če svetlobni vir enakomerno odda eno svečko svetilnosti preko polnega kota enega steradiana, je skupni svetlobni tok, izpuščen v ta kot, en lumen (1 cd · 1 sr = 1 lm). Izotropni svetlobni vir z eno kandelo oddaja celoten svetlobni tok natanko 4π lumnov. Če bi bil vir delno pokrit z idealno absorpcijsko poloblo, bi ta sistem seval pol manj svetlobnega toka - le 2π lumnov. Intenzivnost svetlobe bi bila še vedno ena kandela v tistih smereh, ki niso zakrite.

Lumen lahko mislimo naključno kot merilo skupne količine vidne svetlobe v določenem žarku ali kotu ali pa ga oddaja nek vir. Število kandel ali lumnov iz vira je odvisno tudi od njegovega spektra prek nominalnega odziva človeškega očesa, kot je predstavljen v funkciji svetilnosti.

Razlika med enotami lumen in lux je, da luks upošteva površino, na katero se širi svetlobni tok. Pretok 1000 lumnov, koncentriran na površino enega kvadratnega metra, osvetli ta kvadratni meter z osvetlitvijo 1000 luksov. Isti 1000 lumnov, ki se razprostirajo na desetih kvadratnih metrih, ustvarijo zatemnitev le 100 luksov. Matematično je 1 lx = 1 lm / m 2.

Vir, ki oddaja moč enega vata svetlobe v barvi, za katero je oko najučinkovitejše (valovna dolžina 555 nm, v zelenem območju optičnega spektra), ima svetlobni tok 683 lumnov. Torej lumen predstavlja vsaj 1/683 vatov moči vidne svetlobe, odvisno od spektralne porazdelitve.

Žarnice, ki se uporabljajo za razsvetljavo, so v številnih državah običajno označene s svetlobno močjo v lumnih, kar zahteva zakon.

Spiralna kompaktna fluorescenčna sijalka z močjo 23 W oddaja približno 1.400–1.600 lm. [4] [5] Številne kompaktne fluorescenčne sijalke in drugi alternativni viri svetlobe so označeni kot enakovredni žarnici z določeno močjo. Spodaj je tabela, ki prikazuje tipičen svetlobni tok za običajne žarnice z žarilno nitko in njihovi ustrezniki.

Ekvivalent električne energije za različne svetilke [6] [7] [8]
Najmanjša svetloba (lumni) Poraba električne energije (vati)
Žarilna Kompaktna fluorescentna LED
Nehalogeni Halogen
200 25 3-5 3
450 40 29 9–11 5–8
800 60 13–15 8–12
1,100 75 53 18–20 10–16
1,600 100 72 24–28 14–17
2,400 150 30–52 24-30 [9]
3,100 200 49–75 32 [10]
4,000 300 75–100 40.5 [11]

1. septembra 2010 je začela veljati zakonodaja Evropske unije, ki zahteva, da mora biti svetlobna oprema označena predvsem glede na svetlobni tok (lm), namesto električne moči (W). [12] Ta sprememba je rezultat direktive EU o okoljski zasnovi izdelkov, ki rabijo energijo (IRE). [13] Na primer, v skladu s standardom Evropske unije mora imeti energetsko učinkovita žarnica, za katero se trdi, da je enakovredna 60 W volframove žarnice, najmanjšo svetlobno moč 700–750 lm. [14]

ANSI lumni Uredi

Izhodna svetloba projektorjev (vključno z video projektorji) se običajno meri v lumnih. Ameriški nacionalni inštitut za standardizacijo je vzpostavil standardiziran postopek za testiranje projektorjev, ki vključuje povprečenje več meritev, opravljenih na različnih položajih. [15] Za tržne namene se lahko svetlobni tok projektorjev, preizkušenih po tem postopku, navede v "ANSI lumnih", da jih ločimo od tistih, ki so bili preizkušeni z drugimi metodami. Meritve lumna ANSI so na splošno bolj natančne kot druge merilne tehnike, ki se uporabljajo v industriji projektorjev. [16] To omogoča lažje primerjanje projektorjev na podlagi njihovih specifikacij svetlosti.

Metoda za merjenje ANSI lumnov je opredeljena v dokumentu IT7.215, ki je bil ustvarjen leta 1992. Najprej je projektor nastavljen tako, da prikazuje sliko v sobi pri temperaturi 25 ° C (77 ° F). Svetlost in kontrast projektorja se prilagodita tako, da je v polnem belem polju mogoče razlikovati med 5-odstotnim blokom površine zaslona z 95-odstotno maksimalno belo in dvema enako velikima 100-odstotno in 90-odstotno belim poljem v sredini belega polja. Nato se izmeri svetloba na polnem belem polju na devetih določenih mestih okoli zaslona in izračuna povprečje. To povprečje nato pomnožimo s površino zaslona, ​​da dobimo svetlost projektorja v "ANSI lumnih". [17]

Vrhunski lumni Uredi

Peak lumen je mera svetlobne moči, ki se običajno uporablja pri CRT video projektorjih. Testiranje uporablja testni vzorec, ki je običajno na 10 do 20 odstotkih površine slike bel v sredini zaslona, ​​preostali del pa črn. Izhodna svetloba se meri ravno v tem srednjem območju. Omejitve z CRT video projektorji povzročajo večjo svetlost, če je le del slikovne vsebine v največji svetlosti. Na primer, videoprojektor Sony VPH-G70Q CRT proizvaja 1200 "vršnih" lumnov, a le 200 ANSI lumnov. [18]

Izhod barvne svetlobe Uredi

Svetlost (izhod bele svetlobe) meri skupno količino svetlobe, projicirane v lumnih. Specifikacija svetlosti barv Barvna svetloba meri rdečo, zeleno in modro v devetočkovni mreži z enakim pristopom kot pri merjenju svetlosti.


Razumevanje svetlobnega toka (lumen) in osvetljenosti (lux)

Na embalaži žarnic ali drugih svetilk pogosto vidimo podatke o svetlobnem toku ali osvetlitvi. Mogoče veste, da se ta dva parametra uporabljata za opis svetlosti svetlobe. Katere pa so posebne opredelitve svetlobnega toka in osvetlitve? Kakšna je razlika med njima?

Kaj je svetlobni tok?

Svetlobni tok je mera celotne količine vidne svetlobe, ki jo oddaja svetilka. Se razlikuje od sevalnega toka. Tok sevanja je merjenje vsega oddanega elektromagnetnega sevanja (vključno z infrardečim, ultravijoličnim in vidnim), kar je skupna količina objektivne svetlobe. Svetlobni tok je količina svetlobe, ki jo zazna človeško oko. Odseva občutljivost človeškega očesa s ponderiranjem vsake valovne dolžine s funkcijo svetilnosti. Tako da je utežena vsota vseh valovnih dolžin moči v vidnem svetlobnem pasu, razen infrardečega in ultravijoličnega.

Kaj je funkcija svetilnosti?

Funkcija svetilnosti opisuje relativno občutljivost človeških oči na svetlobo različnih valovnih dolžin s tem, ko subjektivno presoja svetlost svetlobe različnih barv. Ne bi ga smeli šteti za popolnoma natančnega, vendar je dober prikaz vizualne občutljivosti človeškega očesa in je dragocen kot izhodišče za eksperimentalne namene.

Slika 1: Fotopična (črna) in skotopična (zelena) funkcija svetilnosti

Enota Svetlobni tok—— Lumen

Enota SI svetlobnega toka je lumen (lm). Lumen je opredeljen glede na kandelo, ki je enota svetilnosti kot

To pomeni, da kadar je svetlobni kot svetlobnega vira en poln kot in je svetlobni tok 1 lumen, je njegova svetlobna jakost 1 kandela. Kadar je svetlobni tok svetlobnega vira tudi 1 lumen, vendar postane svetlobni kot 1/2 polnega kota, se šteje, da je svetlobna jakost tega svetlobnega vira 2 kandeli.

Nasprotno pa, ko je jakost svetlobe točkovnega svetlobnega vira, ki oddaja svetlobo v vse smeri, 1 kandela, saj ima polna krogla trden kot 4π steradianov, je svetlobni tok tega svetlobnega vira 4 π lumnov ali 12,56 lumnov.

Slika 2: Grafični prikaz 1 steradiana.

Kaj je isvetilnost?

Pri fotometriji je osvetljenost skupni svetlobni tok svetlobe, ki pada na enoto površine. Z drugimi besedami, svetlobni tok predstavlja skupno količino svetlobe, ki jo oddaja vir, medtem ko se osvetljenost nanaša na skupno količino svetlobe, ki jo prejme predmet.

Razmerje med osvetljenostjo in svetlobnim tokom je podobno razmerju med osvetlitvijo in svetlobnim tokom, to je sevalnim tokom, prejetim na enoto površine. Vendar se osvetljenost tehta glede na občutljivost človeških oči na svetlobo različnih valovnih dolžin, kar predstavlja jakost svetlobe, ki jo zaznajo človeške oči.

Enota Osvetljenost—— Lux

Enota osvetljenosti SI je luks (lx). Enako je enemu lumenu na kvadratni meter.

V fotografiji obstaja tudi nemetrična enota osvetlitve, svečka za nogo. Nožna sveča pomeni "osvetlitev vira sveče na površini, oddaljeni eno nogo." Tako je ena sveča enaka enemu lumenu na kvadratni meter ali približno 10 luksov.

Oba Razdalja and Vpliv nagiba Osvetlitev

Osvetljenost je število lumnov na kvadratni meter. To pomeni, da ko svetlobni vir 1000 lumnov osvetli površino 1 kvadratnega metra, je osvetljenost na tej ravnini 1000 lx. Ko vir svetlobe 1000 lumnov osvetli površino 10 kvadratnih metrov, osvetljenost na ravnini postane 100 lx.

Torej, ko kupujemo žarnice, jih ne smemo izbrati samo glede na število lumnov. To je zato, ker kadar so v dnevni sobi in stranišču nameščene žarnice z enakim številom lumnov, je zaradi različne velikosti prostorov razlika med osvetlitvijo in zaznavanjem oči lahko zelo velika.


Razlika med Candelo in Lumenom

Kandela in lumen sta dve enoti, ki se uporabljata za merjenje nekaterih lastnosti svetlobe. Kandela se uporablja za merjenje intenzitete svetilnosti, ki jo zazna človeško oko. Lumen se uporablja za merjenje svetlobnega toka. Obe enoti sta zelo pomembni pri preučevanju svetlobe in drugih elektromagnetnih valov. Na področjih, kot so klasična optika, sodobna optika, elektromagnetna teorija in različna druga področja v fiziki, je potrebno pravilno razumevanje kandele in lumna. V tem članku bomo razpravljali o tem, kaj sta kandela in lumen, kakšne količine se merijo s temi enotami, njihove podobnosti in na koncu razlika med kandelo in lumenom.

Candela je osnovna enota SI. Kandela se uporablja za merjenje svetlobne jakosti vidne svetlobe, ki jo v določeni smeri oddaja določen vir. Svetilnost se meri z množenjem moči oddajanja v določeni smeri, pomnoženo s funkcijo svetilnosti. Funkcija svetilnosti, ki je znana tudi kot funkcija svetlobne učinkovitosti, je funkcija, ki opisuje optično občutljivost očesa za določeno valovno dolžino.

Simbol za kandelo je cd. To je osnovna enota SI. Na splošno sveča oddaja 1 kandelo. Ime koren candela vodi do pomena "sveča". Kandela je opredeljena kot "svetilnost v dani smeri vira, ki oddaja enobarvno sevanje s frekvenco 540 × 1012 herc in ki ima v tej smeri intenzivnost sevanja 1 683 vata na steradian" s 16. generalne konference o utežih in merah leta 1979.

Lumen je enota, ki izhaja iz SI. Lumen je enota, ki se uporablja za merjenje svetlobnega toka. Svetlobni tok je merjenje količine vidne svetlobe, ki pada na človeško oko. Svetlobni tok je odvisen tudi od funkcije svetilnosti. Svetlobni tok lahko dobimo iz svetlobne jakosti, ki jo merimo s kandelo.

Svetlobni tok je oblikovan kot zmnožek svetilnosti in trdnega kota, izmerjenega z upoštevanjem vira kot središča. 1 lumen je enak 1 kandeli steradian. Simbol lumna je lm. Lumen ni osnovna enota SI. Izraz "lumen" se je razvil iz besede svetleč, ki opisuje, kako svetel predmet izgleda.

Tako lumen kot kandela sta odvisna od občutljivosti človeškega očesa.

Kakšna je razlika med Lumenom in Candelo?

• Lumen ni osnovna enota SI, vendar je kandela osnovna enota SI.

• Lumen se uporablja za merjenje svetlobnega toka, kandela pa za merjenje svetilnosti.

• Intenzivnost svetlobe je lastnost samega vira, medtem ko je svetlobni tok odvisen od upoštevanega kota.


Enota svetilnosti

Kandela je enota svetilnosti in je osnovna enota sistema Si. Kandela izhaja iz svetilnosti sveče natančno določene sestave. Sončna svetilnost L ☉ je enota sevalnega toka (moč, oddajana v obliki fotonov), ki jo astronomi običajno uporabljajo za merjenje svetilnosti zvezd, galaksij in drugi nebesni predmeti glede na izhod Sonca. Mednarodna astronomska zveza je eno nominalno svetilnost sonca opredelila kot 3,828 × 10 26 W. Svetilnost Sonca je 3,846 × 10 26 vatov (ali 3,846 × 10 33 ergov na sekundo). Svetilnost je absolutno merilo sevalne moči, to je, da je njena vrednost neodvisna od oddaljenosti opazovalca od predmeta Odgovor: Watts Pojasnilo: V astronomiji je svetilnost skupna količina energije, ki jo v enoti časa odda zvezda, galaksija ali druga astronomski objekt. Kot izraz za oddajanje energije na enoto časa je svetilnost sinonim za moč. V SI un .. Količina, ki meri sposobnost pospeševalnika delcev, da proizvede zahtevano število interakcij, se imenuje svetilnost in je faktor sorazmernosti med številom dogodkov na sekundo dR / dt in presekom p: dR dt = L p: (1) Enota svetilnosti je torej cm2s1

Svetilnost - pretvorbe enot Unitscounter

Enote svetilnosti so nekoliko neintuitivne, pravi Lujan, a nam daje natančno tiste informacije, ki jih potrebujemo. Ko znanstveniki naložijo LHC z novo serijo delcev, ki trčijo,. Svetilnost je merilo energije, ki jo oddaja predmet, na primer zvezda ali galaksija. Za zvezde glavnega zaporedja je svetilnost neposredno povezana z njihovo temperaturo - bolj kot je zvezda bolj vroča, bolj je svetleča. Po drugi strani pa hladnejše zvezde oddajajo manj energije - zato jih je težje opaziti na svetlobi nočnega neba merilo valovne dolžine utežene moči, ki jo odda svetlobni vir v določeni smeri na enoto trdnega kota, na podlagi funkcija svetilnosti, standardiziran model občutljivosti človeškega očesa. Enota svetilnosti SI je kandela (cd), osnovna enota SI Luminosity Gaming je edinstveno postavljena za podporo naraščajoči legiji konkurentov, ustvarjalcev in ambasadorjev, ki so se pridružili naši skupnosti #LGLOYAL, vključno z močnimi ekipami, kot sta Seattle Surge in Vancouver Titans. Korak naprej v prihodnost za nas pri Luminosity Gaming še nikoli ni bil bolj razburljiv

The Galaxy Luminosity Function Earlier in the course, we discussed the luminosity function of stars. We now apply a similar analysis to galaxies, both in the field & in clusters. Consider a sample of galaxies S. We can define the following quantities: n s (L) →Number of galaxies in S per unit luminosity n s (L) dL →Number of galaxies in S. SOAR is a service product owned and operated by LUMINOSITY Ltd., Unit 9, Block C, Calmount Park, Ballymount, Dublin 12, Ireland. VAT No: IE2974100JH | Co Reg 52063 The difference between instantaneous luminosity and integrated luminosity is the difference between, Right now I'm driving at 60 miles per hour, and Over ten hours, I drove 600 miles. For integrated luminosity, physicists switch from squared centimeters to a new unit of area: the barn, a reference to the idiom, Couldn't hit the broad side of a barn

Solar luminosity - Wikipedi

  1. osity is the term that we apply to all wavelengths, regardless of where they lie on the electromagnetic spectrum. Astronomers study the different wavelengths of light from celestial objects by taking the inco
  2. osity The Energy Flux, F, is the power per unit area radiated from an object. The units are energy, area and time. Lu
  3. d with Lumosity, the #1 app with 50+ brain games for memory, math, vocabulary, and more. Start training today
  4. osity would be brighter. Brightness is inversely proportional to distance squared. b= L / 4 pi r^

Since luminosity is defined as the amount of energy emitted by the object, it is given in units of energy per unit time [e.g., J o u l e s / s e c o n d (1 J o u l e / s e c o n d = 1 W a t t) This equation is not rendering properly due to an incompatible browser Introducing the different ways we can characterize the brightness of an object and how we use brightness to study astronomy.Let us know what you think of the.. 5 Luminosity and integrated luminosity For a given beam of flux J striking a target of number density n t and thickness Δx, the rate of interactions for a process having a cross section σ is given by J scat=Jσn tΔx≡Lσ, where the factor L=Jn tΔx=n bv bA bn tΔx multiplying the cross section is known as the luminosity [cm −2 sec−1]

Luminosity astronomy Britannic

  1. Brightness and Flux Density. Astronomers learn about an astronomical source by measuring the strength of its radiation as a function of direction on the sky (by mapping or imaging) and frequency (spectroscopy), plus other quantities (time, polarization) that we ignore for now
  2. osity is 1034 per square centimetre per second. That's a big number, and although we can't say exactly how many collisions it equates to, we can say that and it's around 600 million collisions per second on average
  3. Unit Conversion. A common problem in astronomy is the conversion of a quantity measured in some units into a quantity based on other units. There are also several `systems of measurement' in use in physics and astronomy. The common systems are mks, for meter-kilogram-second, cgs, for centimeter-gram-second, and SI or the System Internationale (SI)
  4. osities 1 Natural units We have been used to using units in which times are measured in seconds and distances in meters. In such units the speed of light takes the value close to 3 × 108 ms−1. We could instead have chosen to use unit of time in seconds and distance in light-seconds
  5. Our Cozine Emergency Enota is a practical solution for your emergency lighting needs. Equipped with a push to test button and a universal K/O pattern on the backplate makes it perfect for any indoor or damp location
  6. Watch full Call of Duty World League match VODs, player interviews, highlights, and more at http://YouTube.com/CODWorldLeague Keep up with Call of Duty World..

What is the unit of luminosity? - Quor

  1. al parameters, it will be necessary to upgrade it for significantly higher lu
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  3. osity is a highly derived unit. The lumen, which is defined in relation to the candela as a light source that uniformly radiates in all directions through a sphere. A full sphere has a solid angle of 4π steradians. The total lu

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.The SI unit of luminous intensity is the candela (cd), an SI base unit In SI derived units illuminance is measured in lux (lx) or lumens per square meter (1 lx = 1 lm/m² = 1 cd·sr·m⁻²). In the CGS system, the unit of illuminance is the phot, which is equal to 10,000 lux. In photography a non-metric unit of illuminance, the foot-candle is often used Flux density gives the power of the radiation per unit area and hence has dimensions of W m − 2 H z − 1 or W m − 2. Observed flux densities are usually extremely small and therefore (especially in radio astronomy) flux densities are often expressed in units of the Jansky (Jy), where 1 Jy = 1 0 − 2 6 W m − 2 H z − 1 Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.. Visit Stack Exchang Luminosity by Unit 7 Noise, released 04 September 202

Luminosity Supply & Solutions 1831 E 73rd, Unit A Denver, CO 80229. 303-287-4332 . Ime. Email Address. Your Message. Cancel × Government Pricing. Luminosity Supply & Solutions has powerful partnerships with quality manufacturers and that's key to providing value to our customers In SI units the standard is 1 lumen per square metre and called 1 lux. Now let's return to flashlights, most of which are designed to be highly directional. If we have a 1 candela (i.e. 1 candlepower) flashlight which just happens to have a beam that illuminates 1 square metre from 1 metre distance , then that square metre will have an illumination of 12.57 lumens, as compared with 1 lumen for. is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars. It is defined in terms of the Sun's output. One solar luminosity is 3.828×1026 W. This does not include the solar neutrino luminosity, which would add 0.023 L☉. The Sun is a weakly variable star, and its luminosity therefore fluctuates

The Unit of Illuminance—— Lux. The SI unit of illuminance is the lux (lx). It is equal to one lumen per square meter. 1 lx = 1 lm/m 2 = 1 cd·sr/m 2. In photography, there is also a non-metric unit of illumination, foot-candle. Foot-candle means the illumination of a candle source on a surface one foot away .Let us look briefly at each of these: 1. Temperature: A black body radiates power at a rate related to its temperature - the hotter the black body, the greater its power output per unit surface area.An incandescent or filament light bulb is an everyday example

Define luminosity. luminosity synonyms, luminosity pronunciation, luminosity translation, English dictionary definition of luminosity. n. illuminance, illumination - the luminous flux incident on a unit area. incandescence - light from heat. glow, luminescence - light from nonthermal sources Clue: ___ per second (luminosity unit) ___ per second (luminosity unit) is a crossword puzzle clue that we have spotted 3 times. There are related clues (shown below) Luminosity, L, is the total outward flow of energy from a radiating body per unit time, in all directions and over all wavelengths. The SI units of luminosity are Watts (W) which quantify the rate of energy transfer in joules per second

unit of luminosity. Physics. ஒளியலகு. English-Tamil dictionary. 2014. unit of illumination unit of mass Look at other dictionaries: Luminosity. Luminosity The luminosity of an object is a measure of its intrinsic brightness and is defined as the amount of energy the object emits in a fixed time. It is essentially the power output of the object and, as such, it can be measured in units such as Watts.. Luminosity Function The number of galaxies in the luminosity range in a given volume is denoted .. • Luminosity - Expressed in solar luminosity, a standard scientific measure. But also can be megawatts. • Distance - Can be parsecs, light years, miles, meters, or kilometers. Parsecs and light years are the most commonly used units since galactic distances are so huge. Proxima Centauri and Siriu

The greater the greater the luminosity of an object, the brighter it appears. An object can be very luminous in multiple wavelengnths of light, from visible light, x-rays, ultraviolet, infrared, microwave, to radio and gamma rays, It often depends on the intensity of the light being given off, which is a function of how energetic the object is 光度学是研究光强弱的学科。不同于辐射度量学,光度学把不同频率的辐射功率用光度函数加权;在天文学中,光度(luminosity)是物体每单位时间内辐射出的总能量,即辐射通量 In astronomy, luminosity is the total amount of energy emitted by a star, galaxy, or other astronomical object per unit time. It is related to brightness, which is the luminosity of an object in a given spectral region. It has been shown that the luminosity of a star (assuming the star is a black body, which is a good approximation) is also related to temperature and radius of the star by the. Luminosity and how far away things are In this class, we will describe how bright a star or galaxy really is by its luminosity. The luminosity is how much energy is coming from the per second. The units are watts (W). Astronomers often use another measure, absolute magnitude. Absolute magnitude is based on a ratio scale, like apparent magnitued

The SI unit for measuring luminance is candela per square meter, which is denoted as cd / m 2. Luminance is often mistaken for luminosity and illuminance due to the similarity of the words, but these three are totally different from each other. What is Illuminance Hi. I am trying to convert the luminosity of a star into solar units. I have a formula but I am not 100% sure it is the right one: L / Lsun= (R / Rsun)2 . (T / Tsun)4 Does R have to be in solar units? And T of course in Kelvin. Would that give me the luminosity of a star in solar units? Hvala Getting more precise, other factors, such as TV screen size also affects the Nits/Lumens relationship. For example, a 65-inch TV that puts out 500 nits will have approximately four times the lumens output of a 32-inch TV putting out 500 nits A team within ASU's Luminosity Lab designed two units to provide a compact and effective way to sterilize personal protective equipment amid the COVID-19 pandemic. The lab's PPE Response Network created a sterilization team that focused on scaling down an original design by Battelle, a technological research and development center This is the distance to use when converting between the bolometric flux from an object at redshift ``z`` and its bolometric luminosity. Parameters-----z : array_like Input redshifts. Returns-----lumdist : `

astropy.units.Quantity` Luminosity distance at each input redshift

Our LuminOsity collection is bold, bright and bursting with colour. Each pattern and design has been originated from individual pieces of traditional letterpress metal type ornamentation and good old fashioned typography to create minimal yet playful upbeat designs that ooze charm, character and beauty candela (unit of luminosity) translation in English-Chinese dictionary. Cookies help us deliver our services. By using our services, you agree to our use of cookies Question: The Luminosity Density (luminosity Per Unit Volume) Of The Old Thin Disk Is Often Modeled With The Functional Form: L(R, Z) = L_o E^-R/hR Sech^2 (z/z_o), Where Sech (z/z_o) = 2/e^z/z_o + E^-z/z_o, Is The Hyperbolic Secant Function. (a) Given Z_o = 2z_thin And L_o TildeEqual 0.05 L CircleDotpc^-3 For The Thin Disk, Plot Its Luminosity Density As A Function. The evolving luminosity function is generally regarded as the best way to summarize the changing demographics of high-redshift galaxies. It is defined as the number of objects per unit comoving volume per unit luminosity, and the data are most often fitted to a Schechter function (Schechter 1976)

Luminosity definition is - the quality or state of being luminous. How to use luminosity in a sentence Use physical units in C++/Down with double! Contribute to mikeford3/units development by creating an account on GitHub , the radiant power emitted by a light-emitting object

candela (unit of luminosity) 英文 - 中文字典的翻 Luminosity of Star = R 2 x T 4. The HR Diagram categorizes stars by surface temperature and luminosity. Hot blue stars, over 30,000 Kelvin, at left and cool red stars, less than 3,000 Kelvin, at. Luminosity is a very fundamental quantity in Astronomy and Astrophysics. Much of what is learnt about celestial objects comes from analyzing their light. This is because the physical processes that occur inside stars gets recorded and transmitted by light. Luminosity is measured in units of energy per second

  • osity of a star represents the amount of power, or energy over time, emitted by the star. 1 Property Details 1.1 Location 1.2 Units 2 Simulation Effects 2.1 Stars The Lu
  • osity. Main Office: 254 36th St Unit C453 Brooklyn, NY 11232. Phone: (888) 998-LEDS (5337
  • Our Cozine Emergency Unit is a practical solution for your emergency lighting needs. Equipped with a push to test button and a universal K/O pattern on the backplate makes it perfect for any indoor or damp location
  • osity is arbitrarily defined as 1.
  • ous intensity. It is the power emitted by a light source in a particular direction, weighted by the lu
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What does 'luminosity' mean in particle physics

Detonation luminosity has been investigated for a long time. The phenomenon is discussed by Johansson and Persson [XVI-7], but they do not mention precursors.Fossé [XVI-8] (Fig. XVI-1), van den Berghe [XVI-9], and Held [XVI-10] have found light ahead of the detonation zone of porous explosives. The interpretation has been in terms of luminous air shocks or scattering of detonation luminosity. So, if we determine a star's radius (for example, with the small angle formula) and its luminosity (in units of solar luminosities) we directly derive its temperature! Conversely, if we know its temperature and its luminosity, we can determine its radius! That is where the Herzprung-Russel diagram starts to grow in all of its power Unit 3: Morgan-Keenan Luminosity Class 1. BY COSMOS - THE SAO ENCYCLOPEDIA OF ASTRONOMY A classification of stars is based primarily on their temperatures. 3 MORGAN-KEENAN LUMINOSITY CLAS Obviously, as can be seen from the diagram above, two stars can have the same apparent magnitude, despite having a very different intrinsic brightness, due to their differing distances from Earth. The total power output of a star, or its intrinsic brightness is called its luminosity, and is measured in #92units$

I'm looking for some kind of formula or algorithm to determine the brightness of a color given the RGB values. I know it can't be as simple as adding the RGB values together and having higher sums.. One solar luminosity unit, therefore, is equal to about 3.839×1026 W, or 3.839×1033 erg/s, or the Sun's commonly accepted luminosity. However, the Sun's luminosity does not always stay the same it frequently fluctuates. The solar cycle (sunspot cycle), which lasts for eleven years, causes a variation of about ±0.1% Luminosity Supply & Solutions is a certified woman owned lighting and electrical distribution company that was founded in 1993. We are manufacturer-neutral, so our focus is entirely on reliable, high quality, high efficiency, and cost-effective products Luminosity = (Flux)(Surface Area) = (SigmaT 4) (4(pi)R 2) While it is possible to compute the exact values of luminosities, it requires that we know the value of Sigma. We can get around this by comparing the luminosities of two objects, either two different objects, or the same object before or after some great change in temperature, radius, or both

Luminosity Calculato

Featuring the bright and bouncy LuminOsity patterns. Our quality Osity patterned papers are traditionally printed using 100% recycled uncoated paper. Perfect for bookbinding, paper craft and origami or use as a wrap for a beautiful gift luminosity L of a star is the amount of energy in Joules it actually radiates per second (that is, its power) and is measured in watts, W. The intensity of the radiation is defined as the intensity, I, of a star: = 4 2 The unit of brightness is Wm−2

Conclusion. We now know enough to formulate a concise definition for illuminance: the perceived level of ambient brightness, taking into account the objective light intensity and the spectral response of the human eye.Thus, the lux value in a particular environment depends on the amount of light produced by natural and/or artificial sources as well as the spectral characteristics of this light Consider that we already know that the Sun has m = -26.8, and it is located at 1 A.U. (astronomical unit) from us. 1 A.U. = 1.5 x 10 13 cm = 4.85 x 10-6. pc = semimajor axis of earth's orbit. The sun has a luminosity of 1 solar luminosity L sun = 3.9 x 10 33 erg s-1

Luminosity Gaming is a Canadian eSports organization . Luminosity also fields teams in Call of Duty, Counter-Strike: Global Offensive, Hearthstone: Heroes of Warcraft, Overwatch, King of the Kill and World of Warcraft This relationship, known as the mass-luminosity relation, is shown graphically in Figure 18.9. Each point represents a star whose mass and luminosity are both known. The horizontal position on the graph shows the star's mass, given in units of the Sun's mass, and the vertical position shows its luminosity in units of the Sun's luminosity where L is the luminosity of the central source at the cloud and k is the mass absorption coefficient of the cloud, (i.e. the cross section per unit mass) and is defined by k n = k n r. Figure 6.5: A small mass element m a distance r from a luminous body of mass to luminosity ratio M/L experiences an outward force due to radiation pressure, F rad and an inward force due to gravity F grav Luminosity and the Distance to Stars - the inverse-square relationship section for 8.5 The Cosmic Engine, HSC Physics Astronomers actually use a unit of distance called the parsec (pc) to express distances to other stars and galaxies Installation of the TDIS unit for the High-Luminosity LHC. Nearly one year after the start of the assembly activities the first 3-module-device Target Dump Injection Segmented (TDIS) unit is ready to be installed

# Sensor luminosity - platform: mqtt name: Luminosidade_garagem state_topic: sensor/luminosity qos: 0 unit_of_measurement: cd Restart Home Assistant after adding the sensor. And here's an example on how to get the values from the sensor - condition: numeric_state entity_id: 'sensor.Luminosidade_garagem' below: 45 July 7, 2020. Students in the Arizona State University Luminosity Lab have created two versions of a low-cost, small-scale sterilization unit that is effective on general personal protective equipment, including increasingly scarce N95 masks The luminosity of a star is given by the equation. L = 4pR 2 s T 4, Where L is the luminosity in Watts, R is the radius in meters, s is the Stefan-Boltzmann constant (5.67 x 10-8 Wm-2 K-4), and T is the star's surface temperature in Kelvin. The temperature of a star is related to its b-v magnitude Flux (or radiant flux), F, is the total amount of energy that crosses a unit area per unit time. Flux is measured in joules per square metre per second (joules/m 2 /s), or watts per square metre (watts/m 2)

查看CWL Global Pro League, Group stage上Luminosity Gaming vs Units的Call of Duty比赛的结果、得分、赔率等信息. Absolute Magnitude = Luminosity, although in different units. Luminosity and Brightness of the Sun Sun's Brightness = 1370 Watts/m 2 Sun's Distance (d) = 1.5 x 10 11 m Therefore, Area of Sphere is 4 (pi) d 2 = 4 (pi) (1.5 x 10 11 m) 2 = 3 x 10 23 m 2 Luminosity= (1370 Watts/m 2)(3 x 10 23 m 2) = 4 x 10 26 Watt where ϕ * is the normalization density, L * is a characteristic luminosity, and α is the power-law slope at low luminosity, L.The faint-end slope, α, is usually negative (α ≃ -1.3 in the local Universe e.g. Hammer et al. 2012) implying large numbers of faint galaxies. In the high-redshift galaxy literature, the UV continuum luminosity function is usually presented in units of per. Figure 10: Logarithm of the ratio of the total bolometric radiated luminosity (as calculated from the [Oiii] emission line see Section 2.3.1) per unit volume due to emission-line AGNs of a given blac..

In contrast, the very common red, cool, low-luminosity stars at the lower end of the main sequence are much smaller and more compact than the Sun. An example of such a red dwarf is Ross 614B, with a surface temperature of 2700 K and only 1/2000 of the Sun's luminosity. We call such a star a dwarf because its diameter is only 1/10 that of the Sun Luminosity Gaming is an esports organization based in Canada. They currently field teams in Fortnite, H1Z1, Counter Strike: Global Offensive, and Smite. Their parent company, Enthusiast Gaming, own the Seattle Surge.. History [] Black Ops 3 []. On November 9, 2015, Luminosity Gaming announced their expansion into Call of Duty eSports with the signing of Replays, ProoFy, Spacely, and John for. 2. Luminosity is an absolute measure of radiated electromagnetic power, the radiant power emitted by a light-emitting object. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical object. 3. Luminosity depends on temperature and size. 4. 6000 Kelvi There is tremendous heterogeneity in luminosity across Indian regions such as between the South (high luminosity) and East (low luminosity). Nevertheless, there is also heterogeneity between contiguous districts. Our analysis explores whether higher education can account for differences in luminosity across districts within the same state

Luminous intensity - Wikipedi

Absolute parameters of 509 main-sequence stars selected from the components of detached eclipsing spectroscopic binaries in the solar neighbourhood are used to study mass-luminosity, mass-radius, and mass-effective temperature relations (MLR, MRR, and MTR). The MLR function is found better if expressed by a six-piece classical MLR (L ∝ M α</SUP>) rather than a fifth or a sixth degree. svetilnost (or the same abs. magnitude M), but a similar result applies otherwise. The only difference is that the constant C depends on M for each subgroup of stars. Thus N(m) = C *10 0.6 m , while the number of stars per enota apparent magnitude is A(m): A(m) = dN/dm = C210 0.6 m Recall then, that the total brightness received from all stars o qualitatively describe color are: brightness, hue, and saturation (analogous to luminosity, dominant wavelength, and excitation purity, respectively). These terms (and others) are often used interchangeably. Here we will adhere to the official terms assigned to the CIE system to avoid any ambiguity. 2. Luminosity Vertical axisstellar luminosity in units of Suns luminosity Lsun Stars near from ASTR 102 at Vanderbilt Universit


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Two basic photometric concepts, luminous flux and luminous intensity have been briefly described and a simple approximate calculator to convert between the two is available in this page. Than some aspects of the conversion between radiant and luminous flux have been explained, but unfortunately, there is no simple way to convert between them. Finally lamp luminous efficacy has been discussed. The goal is to help comparing lamps or light sources in general when complete technical data is not available.


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The kandela 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. Luminous intensity is analogous to radiant intensity, but instead of simply adding up the contributions of every wavelength of light in the source's spectrum, the contribution of each wavelength is weighted by the standard luminosity function. A common wax candle emits light with a luminous intensity of roughly one candela. If emission in some directions is blocked by an opaque barrier, the emission would still be approximately one candela in the directions that are not obscured.

Svetilnost is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls within a given solid angle.

Svetilnost is an absolute measure of radiated electromagnetic power (light), the radiant power emitted by a light-emitting object.

In photometry, svetilnost 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. The SI unit of luminous intensity is the candela (cd), an SI base unit.

Photometry is the science of the measurement of light, in terms of its zaznati brightness to the human eye. It is distinct from radiometry, which is the science of measurement of radiant energy in terms of absolute power. In modern photometry, the radiant power at each wavelength is weighted by a luminosity function that models human brightness sensitivity. Typically, this weighting function is the photopic sensitivity function, although the scotopic function or other functions may also be applied in the same way.

A nožna sveča is a non-SI unit of illuminance or light intensity. The foot-candle is defined as one lumen per square foot. This unit is commonly used in lighting layouts in parts of the world where United States customary units are used, mainly the United States. Most of the world uses the corresponding SI derived unit lux, defined as one lumen per square meter.

V radiometriji radiance is the radiant flux emitted, reflected, transmitted or received by a given surface, per unit solid angle per unit projected area. Spectral radiance is the radiance of a surface per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. To so usmerjena quantities. The SI unit of radiance is the watt per steradian per square metre, while that of spectral radiance in frequency is the watt per steradian per square metre per hertz and that of spectral radiance in wavelength is the watt per steradian per square metre per metre —commonly the watt per steradian per square metre per nanometre. The microflick is also used to measure spectral radiance in some fields. Radiance is used to characterize diffuse emission and reflection of electromagnetic radiation, or to quantify emission of neutrinos and other particles. Historically, radiance is called "intensity" and spectral radiance is called "specific intensity". Many fields still use this nomenclature. It is especially dominant in heat transfer, astrophysics and astronomy. "Intensity" has many other meanings in physics, with the most common being power per unit area.

V radiometriji obsevanje je sevalni tok (moč) prejeli avtor a površino na enoto površine. The SI unit of irradiance is the watt per square metre (W⋅m 𕒶 ). The CGS unit erg per square centimetre per second (erg⋅cm 𕒶 ⋅s 𕒵 ) is often used in astronomy. Obsevanju pogosto rečemo intenzivnost, vendar se temu izrazu izogibamo v radiometriji, kjer takšna uporaba povzroči zamenjavo z intenzivnostjo sevanja. V astrofiziki se imenuje obsevanje sevalni tok.

In photometry, luminous flux ali luminous power is the measure of the perceived power of light. It differs from radiant flux, the measure of the total power of electromagnetic radiation, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light.

In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception. Podobno, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance.

A phot (ph) is a photometric unit of illuminance, or luminous flux through an area. It is not an SI unit but rather is associated with the older centimetre–gram–second system of units. The name was coined by André Blondel in 1921.

The lumen is the SI derived unit of luminous flux, a measure of the total quantity of visible light emitted by a source per unit of time. Luminous flux differs from power in that radiant flux includes all electromagnetic waves emitted, while luminous flux is weighted according to a model of the human eye's sensitivity to various wavelengths. Lumens are related to lux in that one lux is one lumen per square metre.

V radiometriji radiant intensity is the radiant flux emitted, reflected, transmitted or received, per unit solid angle, and spectral intensity is the radiant intensity per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. To so usmerjena quantities. The SI unit of radiant intensity is the watt per steradian, while that of spectral intensity in frequency is the watt per steradian per hertz and that of spectral intensity in wavelength is the watt per steradian per metre —commonly the watt per steradian per nanometre. Radiant intensity is distinct from irradiance and radiant exitance, which are often called intenzivnost in branches of physics other than radiometry. In radio-frequency engineering, radiant intensity is sometimes called radiation intensity.

In radiometry, photometry, and color science, a spectral power distribution (SPD) measurement describes the power per unit area per unit wavelength of an illumination. Splošneje izraz spectral power distribution can refer to the concentration, as a function of wavelength, of any radiometric or photometric quantity.

Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power, measured in lumens per watt in the International System of Units (SI). Depending on context, the power can be either the radiant flux of the source's output, or it can be the total power consumed by the source. Which sense of the term is intended must usually be inferred from the context, and is sometimes unclear. The former sense is sometimes called luminous efficacy of radiation, and the latter luminous efficacy of a light source ali overall luminous efficacy.

A foot-lambert ali footlambert is a unit of luminance in United States customary units and some other unit systems. A foot-lambert equals 1/π or 0.3183 candela per square foot, or 3.426 candela per square meter. The foot-lambert is named after Johann Heinrich Lambert (1728�), a Swiss-German mathematician, physicist and astronomer. It is rarely used by electrical and lighting engineers, in favor of the candela per square foot or candela per square meter.

In photometry, luminous energy is the perceived energy of light. This is sometimes called the quantity of light. Luminous energy is not the same as radiant energy, the corresponding objective physical quantity. This is because the human eye can only see light in the visible spectrum and has different sensitivities to light of different wavelengths within the spectrum. When adapted for bright conditions, the eye is most sensitive to light at a wavelength of 555 nm. Light with a given amount of radiant energy will have more luminous energy if the wavelength is 555 nm than if the wavelength is longer or shorter. Light whose wavelength is well outside the visible spectrum has a luminous energy of zero, regardless of the amount of radiant energy present.

Several measures of svetloba are commonly known as intenzivnost:

V radiometriji sevalni tok ali radiant power is the radiant energy emitted, reflected, transmitted or received, per unit time, and spectral flux ali 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. The SI unit of radiant flux is the watt (W), that is the joule per second in SI base units, while that of spectral flux in frequency is the watt per hertz and that of spectral flux in wavelength is the watt per metre —commonly the watt per nanometre.

V radiometriji radiant exitance ali radiant emittance is the radiant flux emitted by a surface per unit area, whereas spectral exitance ali spectral emittance is the radiant exitance of a surface per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. This is the emitted component of radiosity. The SI unit of radiant exitance is the watt per square metre, while that of spectral exitance in frequency is the watt per square metre per hertz (W·m 𕒶 ·Hz 𕒵 ) and that of spectral exitance in wavelength is the watt per square metre per metre (W·m 𕒷 )—commonly the watt per square metre per nanometre. The CGS unit erg per square centimeter per second is often used in astronomy. Radiant exitance is often called "intensity" in branches of physics other than radiometry, but in radiometry this usage leads to confusion with radiant intensity.