natgillin/translations-raw huggingface dataset:
Application of the test mixture to the headlamp
Nanašanje preskusne mešanice na žaromet
The test mixture shall be uniformly applied to the entire light emitting surface of the headlamp and then left to dry.
Preskusno mešanico je treba enakomerno nanesti na celotno svetlečo površino žarometa in nato pustiti, da se posuši.
This procedure shall be repeated until the illumination value has dropped to 15-20 % of the values measured for each following point under the conditions described in this annex:
Postopek je treba ponavljati, dokler vrednost osvetljenosti ne pade na 15–20 % vrednosti, ki so bile izmerjene za naslednjo točko pod pogoji, opisanimi v tej prilogi:
50 R and 50 V [5] for a passing lamp only, designed for right-hand traffic.
50 R in 50 V [5] le pri žarometu za kratki svetlobni pramen, zasnovanem za vožnjo po desni strani cestišča.
50 L and 50 V for a passing lamp only, designed for left-hand traffic.
50 L in 50 V le pri žarometu za kratki svetlobni pramen, zasnovanem za vožnjo po levi strani cestišča.
The measuring equipment shall be equivalent to that used during headlamp approval tests.
Merilna oprema mora ustrezati opremi, ki je bila uporabljena pri preskusih za homologacijo žarometa.
A standard (reference) filament lamp shall be used for the photometric verification.
Za fotometrično preverjanje je treba uporabiti etalonsko (referenčno) žarnico z žarilno nitko.
TEST FOR CHANGE IN VERTICAL POSITION OF THE CUT-OFF LINE UNDER THE INFLUENCE OF HEAT
PRESKUS SPREMEMBE NAVPIČNE LEGE MEJE SVETLO-TEMNO POD VPLIVOM TOPLOTE
This test consists of verifying that the vertical drift of the cut-off line under the influence of heat does not exceed a specified value for an operating passing lamp.
Pri tem preskusu se preverja, ali navpični premik meje svetlo-temno pod vplivom toplote pri delujočem žarometu za kratki svetlobni pramen presega predpisane vrednosti.
The headlamp tested in accordance with paragraph 1 of this annex shall be subjected to the test described in paragraph 2.1 of this annex without being removed from or readjusted in relation to its test fixture.
Na žarometu, ki je bil preskušen v skladu z odstavkom 1 te priloge, se opravi preskus, opisan v odstavku 2.1, ne da bi ga odstranili iz preskusne vpenjalne naprave ali spremenili njegovo lego v njej.
The test shall be carried out in a dry and still atmosphere at an ambient temperature of 23 °C ± 5 °C.
Preskus se izvede v suhem in mirnem ozračju pri temperaturi okolja 23 °C ± 5 °C.
Using a mass production filament lamp which has been aged for at least one hour the headlamp shall be operated on passing beam without being dismounted from or readjusted in relation to its test fixture.
Ob uporabi serijske žarnice z žarilno nitko, ki je bila starana vsaj eno uro, mora žaromet delovati s kratkim svetlobnim pramenom, ne da bi ga vzeli iz preskusne vpenjalne naprave ali spremenili njegovo lego v njej.
The measurement of the variation in the cut-off line position as described above shall be carried out by any method giving acceptable accuracy and reproducible results.
Meritev spremembe lege meje svetlo-temno, opisano zgoraj, je treba izvesti s katero koli metodo, ki daje zadosti točne in ponovljive rezultate.
The result expressed in milliradians (mrad) shall be considered as acceptable when the absolute value Δ rI = r3 – r60 recorded on the headlamp is not more than 1,0 mrad (Δ rI ≤ 1,0 mrad).
Rezultat, izražen v miliradianih (mrad), se šteje kot sprejemljiv, če absolutna vrednost Δ rI = r3 – r60, izmerjena na tem žarometu, ni večja od 1,0 mrad (Δ rI ≤ 1,0 mrad).
However, if this value is more than 1,0 mrad but not more than 1,5 mrad (1,0 mrad < Δ rI ≤ 1,5 mrad) a second headlamp shall be tested as described in paragraph 2.1 of this annex after being subjected three consecutive times to the cycle as described below, in order to stabilise the position of mechanical parts of the headlamp on a base representative of the correct installation on the vehicle:
Če je ta vrednost večja od 1 mrad, vendar ne večja od 1,5 mrad (1 mrad < ΔrI ≤ 1,5 mrad), je treba opraviti preskus na drugem žarometu, kakor je opisano v odstavku 2.1 te priloge, in sicer potem, ko je bil žaromet trikrat zaporedoma izpostavljen ciklu, kakor je opisano spodaj, zaradi stabiliziranja lege mehanskih delov žarometa na vpenjalni napravi, ki ustreza pravilni vgradnji na vozilu:
Operation of the passing lamp for one hour (the voltage shall be adjusted as specified in paragraph 1.1.1.2 above).
Enourno delovanje žarometa za kratki svetlobni pramen (napetost je treba prilagoditi skladno z odstavkom 1.1.1.2).
Period of rest for one hour.
Enourno mirovanje.
The headlamp type shall be considered as acceptable if the mean value of the absolute values Δ rI measured on the first sample and Δ rII measured on the second sample is not more than 1,0 mrad
Tip žarometa velja za sprejemljivega, če srednja vrednost absolutnih vrednosti Δ rI, izmerjena za prvi vzorec, in Δ rII, izmerjena za drugi vzorec, ne presega 1 mrad.
When the tested headlamp is grouped and/or reciprocally incorporated with signalling lamps, the latter shall be lit for the duration of the test.
Če je preskušani žaromet združen in/ali integriran s signalnimi svetilkami, morajo biti te med preskusom ves čas vklopljene.
In the case of a direction indicator lamp, it shall be lit in flashing operation mode with an on/off time ratio of approximately one to one.
Smerna svetilka mora biti vklopljena v načinu utripanja, pri čemer naj bo časovno razmerje med vklopom in izklopom približno ena proti ena.
Should two or more lamp filaments be simultaneously lit when headlamp flashing is used, this shall not be considered as being normal use of the filaments simultaneously.
Če med uporabo svetlobne hupe hkrati svetita dve ali več žarilnih nitk, to ne šteje za običajno hkratno uporabo žarilnih nitk.
NaCMC represents the sodium salt of carboxymethylcellulose, customarily referred to as CMC.
NaCMC predstavlja natrijevo sol karboksimetilceluloze, ki se običajno označuje kot CMC.
The tolerance on quantity is due to the necessity of obtaining a dirt that correctly spreads out on all the plastic lens.
Potrebna je količinska toleranca, da se dobi umazanija, ki se pravilno porazdeli po celotni plastični leči.
is situated 375 mm below HV on the vertical line v-v on the screen at 25 m distance.
Točka 50 V je 375 mm pod HV na navpični črti v-v na zaslonu, oddaljenem 25 m.
(See paragraph 4 of this Regulation)
(Glej odstavek 4 tega pravilnika)
a = 12 mm min.
a = najmanj 12 mm
The headlamp bearing the approval marking shown above is a headlamp meeting the requirements of this Regulation in respect of both the driving beam and the passing beam, and which is designed for right-hand traffic only.
Žaromet z zgornjo homologacijsko oznako je žaromet, ki izpolnjuje zahteve tega pravilnika v zvezi z dolgim in kratkim svetlobnim pramenom in je zasnovan le za vožnjo po desni strani cestišča.
The approval number and the additional symbols shall be placed close to the circle and either above or below the letter ‘E’, or to the right or left of that letter.
Številka homologacije in dodatni simboli morajo biti v bližini kroga in bodisi nad bodisi pod črko „E“ ali desno ali levo od te črke.
The digits of the approval number shall be on the same side of the letter ‘E’ and face the same direction.
Števke v številki homologacije morajo biti na isti strani črke „E“ in obrnjene v isto smer.
The use of Roman numerals as approval numbers should be avoided so as to prevent any confusion with other symbols.
V številki homologacije se je treba izogniti uporabi rimskih številk, da se prepreči kakršna koli zamenjava z drugimi simboli.
The headlamp bearing the approval mark shown above is a headlamp meeting the requirements of this Regulation with respect to both the passing beam and the driving beam, and designed:
Žaromet z zgornjo homologacijsko oznako je žaromet, ki izpolnjuje zahteve tega pravilnika v zvezi s kratkim in dolgim svetlobnim pramenom in je zasnovan:
For both traffic systems, by means of an adjustment as desired of the optical unit or the lamp.
za vožnjo po obeh straneh cestišča, z ustrezno nastavitvijo optične enote ali žarnice.
The headlamp bearing the approval mark shown above is a headlamp incorporating the lens of plastic material meeting the requirements of this Regulation with respect to the passing beam only, and designed:
Žaromet z zgornjo homologacijsko oznako je žaromet z lečo iz plastičnega materiala, ki izpolnjuje zahteve tega pravilnika le v zvezi s kratkim svetlobnim pramenom in je zasnovan:
For both traffic systems.
za vožnjo po obeh straneh cestišča.
For right-hand traffic only.
le za vožnjo po desni strani cestišča.
The headlamp bearing the approval mark shown above is a headlamp meeting the requirements of this Regulation:
Žaromet z zgornjo homologacijsko oznako je žaromet, ki izpolnjuje zahteve tega pravilnika:
With respect to the passing beam only, and designed for left-hand traffic only.
le v zvezi s kratkim svetlobnim pramenom in je zasnovan le za vožnjo po levi strani cestišča.
With respect to the driving beam only.
le v zvezi z dolgim svetlobnim pramenom.
Identification of a headlamp incorporating the lens of plastic material meeting the requirements of Regulation No 1:
Identifikacija žarometa z lečo iz plastičnega materiala, ki izpolnjuje zahteve Pravilnika št. 1:
For both the passing beam and the driving beam and designed for right-hand traffic only.
Za kratki in dolgi svetlobni pramen ter je zasnovan le za vožnjo po desni strani cestišča.
For the passing beam only and designed for left-hand traffic only.
Le za kratki svetlobni pramen in je zasnovan le za vožnjo po levi strani cestišča.
The passing lamp filament shall not be lit simultaneously with the driving lamp filament and/or any other headlamp with which it is reciprocally incorporated.
Žarilna nitka žarometa za kratki svetlobni pramen ne sme svetiti hkrati z žarilno nitko žarometa za dolgi svetlobni pramen in/ali katerim koli drugim žarometom, s katerim je integrirana.
Simplified marking of grouped, combined or reciprocally incorporated lamps
Poenostavljeno označevanje združenih, kombiniranih ali integriranih svetilk
They are not part of the approval mark.)
Črte niso del homologacijske oznake)
Note: The four examples shown above correspond to a lighting device bearing an approval mark relating to:
Opomba: Štirje primeri, prikazani zgoraj, ustrezajo svetlobni napravi s homologacijsko oznako, ki se nanaša na:
A front Position lamp approved in accordance with the 01 series of amendments to Regulation No 7,
prednjo pozicijsko svetilko, homologirano v skladu s spremembami 01 Pravilnika št. 7,
A headlamp with a passing beam designed for right-hand and left-hand traffic and a driving beam, approved in accordance with the 01 series of amendments to Regulation No 1 and incorporating a lens of plastic material,
žaromet za kratki svetlobni pramen, zasnovan za vožnjo po desni in levi strani cestišča, in za dolgi svetlobni pramen, ki je bil homologiran v skladu s spremembami 01 k Pravilniku št. 1 in vključuje lečo iz plastičnega materiala,
A front fog lamp approved in accordance with the 02 series of amendments to Regulation No 19 and incorporating a lens of plastic material,
žaromet za meglo, ki je bil homologiran v skladu s spremembami 02 Pravilnika št. 19 in vključuje lečo iz plastičnega materiala,
A front direction indicator lamp of category 1a approved in accordance with the 02 series of amendments to Regulation No 6.
prednjo smerno svetilko kategorije 1a, homologirano v skladu s spremembami 02 Pravilnika št. 6.
The above example corresponds to the marking of a lens of plastic material intended to be used in different types of headlamps, namely:
Zgornji primer ustreza oznaki leče iz plastičnega materiala, ki je predvidena za uporabo v različnih tipih žarometov, in sicer:
either: a headlamp with a passing beam designed for right-hand and left-hand traffic and a driving beam with a maximum intensity comprised between 86250 and 101250 candelas, approved in Germany (E1) in accordance with the requirements of Regulation No 20 as amended by the 02 series of amendments,
bodisi: v žarometu za kratki svetlobni pramen, zasnovanem za vožnjo po desni in levi strani cestišča, in za dolgi svetlobni pramen z največjo svetilnostjo med 86250 in 101250 kandelami, ki je bil homologiran v Nemčiji (E1) v skladu z zahtevami Pravilnika št. 20, kakor je bil spremenjen s spremembami 02,
which is reciprocally incorporated with
ki je integriran s
a front position lamp approved in accordance with the 01 series of amendments to Regulation No 7;
prednjo pozicijsko svetilko, homologirano v skladu s spremembami 01 Pravilnika št. 7;
a headlamp with a passing beam designed for passing beam designed for right-hand and left-hand traffic and a driving beam, approved in Germany (E1) in accordance with the requirements of Regulation No 1 as amended by the 01 series of amendments,
bodisi: v žarometu za kratki svetlobni pramen, zasnovanem za vožnjo po desni in levi strani cestišča, in za dolgi svetlobni pramen, ki je bil homologiran v Nemčiji (E1) v skladu z zahtevami Pravilnika št. 1, kakor je bil spremenjen s spremembami 01,
which is reciprocally incorporated with the same front position lamp as above;
ki je integriran z enako prednjo pozicijsko svetilko kot zgoraj;
or even: either of the above-mentioned headlamps approved as a single lamp.
ali celo: v katerem koli izmed zgoraj navedenih žarometov, ki je bil homologiran kot ena svetilka.
The main body of the headlamp shall bear the only valid approval number, for instance:
Ohišje žarometa mora biti označeno z edino veljavno številko homologacije, npr.:
The above example corresponds to the marking of a lens of plastic material used in an assembly of two headlamps approved in France (E2), consisting of a headlamp emitting a passing beam designed for both traffic systems and of a driving beam with a maximum intensity comprised between x and y candelas, meeting the requirements of Regulation No 1, as amended by the 01 series of amendments and of a headlamp emitting a driving beam with a maximum intensity comprised between w and z candelas, meeting the requirements of Regulation No 20, as amended by the 02 series of amendments the maximum intensity of all the driving beams being comprised between 86250 and 101250 candelas.
Zgornji primer ustreza oznaki leče iz plastičnega materiala, ki je uporabljena v sklopu dveh žarometov, homologiranem v Franciji (E2) in sestavljenem iz žarometa, ki oddaja kratki svetlobni pramen, zasnovan za vožnjo po obeh straneh cestišča, in dolgi svetlobni pramen z največjo svetilnostjo med x in y kandelami, ki izpolnjuje zahteve Pravilnika št. 1, kakor je bil spremenjen s spremembami 01, ter žarometa, ki oddaja dolgi svetlobni pramen z največjo svetilnostjo med w in z kandelami in izpolnjuje zahteve Pravilnika št. 20, kakor je bil spremenjen s spremembami 02; največja svetilnost vseh dolgih svetlobnih pramenov je med 86250 in 101250 kandelami.
MEASURING SCREENS
MERILNI ZASLONI
(Dimensions in mm)
(dimenzije v mm)
Axis of road
Os ceste
Standard european beam
Standardni evropski svetlobni pramen
passing through focus of headlamp
poteka skozi fokus žarometa
Measuring points of illumination values
Točke merjenja vrednosti osvetljenosti
Note: Figure shows the measuring points for right-hand traffic.
Opomba: Slika prikazuje merilne točke za vožnjo po desni strani cestišča.
Requirements for lamps incorporating lenses of plastic material — testing of lens or material samples and of complete lamps
Zahteve za žaromete z lečami iz plastičnega materiala – preskušanje vzorcev leč ali materiala in celotnih žarometov
The samples supplied pursuant to paragraph 2.2.4 of this Regulation shall satisfy the specifications indicated in paragraphs 2.1 to 2.5 below.
Vzorci, predloženi skladno z odstavkom 2.2.4 tega pravilnika, morajo ustrezati specifikacijam iz odstavkov od 2.1 do 2.5.
The two samples of complete lamps supplied pursuant to paragraph 2.2.3 of this Regulation and incorporating lenses of plastic material shall, with regard to the lens material, satisfy the specifications indicated in paragraph 2.6 below.
Vzorca celotnih žarometov, predložena skladno z odstavkom 2.2.3 tega pravilnika in opremljena z lečami iz plastičnega materiala, morata glede materiala leč ustrezati specifikacijam iz odstavka 2.6.
The samples of lenses of plastic material or samples of material shall be subjected, with the reflector to which they are intended to be fitted (where applicable), to approval tests in the chronological order indicated in table A reproduced in appendix 1 to this annex.
Na vzorcih leč iz plastičnega materiala ali na vzorcih materiala skupaj z reflektorjem, na katerega bodo pritrjene (kjer to pride v poštev), je treba opraviti homologacijske preskuse v časovnem zaporedju, določenem v tabeli A Dodatka 1 k tej prilogi.
However, if the lamp manufacturer can prove that the product has already passed the tests prescribed in paragraphs 2.1-2.5 below, or the equivalent tests pursuant to another Regulation, those tests need not be repeated; only the tests prescribed in appendix 1, table B, shall be mandatory.
Če pa proizvajalec žarometov lahko dokaže, da so bili na izdelku že opravljeni preskusi, predpisani v odstavkih od 2.1 do 2.5 spodaj, ali enakovredni preskusi skladno s katerim drugim pravilnikom, teh preskusov ni treba ponoviti; obvezni so le preskusi, predpisani v tabeli B Dodatka 1.
Three new samples (lenses) shall be subjected to five cycles of temperature and humidity (RH = relative humidity) change in accordance with the following programme:
Na treh novih vzorcih (lečah) je treba v petih ciklih spreminjajoče se temperature in vlažnosti (RH = relativna vlažnost) opraviti preskuse po naslednjem programu:
3 hours at 40 °C ± 2 °C and 85-95 % RH;
3 ure pri temperaturi 40 °C ± 2 °C in relativni vlažnosti 85–95 %;
1 hour at 23 °C ± 5 °C and 60-75 % RH;
1 uro pri temperaturi 23 °C ± 5 °C in relativni vlažnosti 60–75 %;
15 hours at – 30 °C ±2 °C;
15 ur pri temperaturi –30 °C ± 2 °C;
3 hours at 80 °C ± 2 °C;
3 ure pri temperaturi 80 °C ± 2 °C;
1 hour at 23 °C ± 5 °C and 60-75 % RH.
1 uro pri temperaturi 23 °C ± 5 °C in relativni vlažnosti 60–75 %;
Before this test, the samples shall be kept at 23 °C ± 5 °C and 60-75 % RH for at least four hours.
Pred tem preskusom morajo biti vzorci najmanj štiri ure izpostavljeni temperaturi 23 °C ± 5 °C in relativni vlažnosti 60–75 %.
Note: The periods of one hour at 23 °C ± 5 °C shall include the periods of transition from one temperature to another which are needed in order to avoid thermal shock effects.
Opomba: V enournih časovnih obdobjih s temperaturo 23° ± 5 °C je vključen čas za prehod z ene temperature na drugo, ki je potreben za preprečevanje učinkov toplotnih šokov.
Photometric measurements shall be carried out on the samples before and after the test.
Pred preskusom in po njem je treba na vzorcih opraviti fotometrične meritve.
These measurements shall be made using a standard lamp, at the following points:
Te meritve je treba opraviti z etalonsko žarnico v naslednjih točkah:
B 50 L and 50 R for the passing beam of a passing lamp or a passing/driving lamp (B 50 R and 50 L in the case of headlamps intended for left-hand traffic);
B 50 L in 50 R za kratki svetlobni pramen žarometa za kratki svetlobni pramen ali žarometa za kratki/dolgi svetlobni pramen (B 50 R in 50 L za žaromete, namenjene vožnji po levi strani cestišča);
Emax route for the driving beam of a driving lamp or a passing/driving lamp;
Emax pot za dolgi svetlobni pramen žarometa za dolgi svetlobni pramen ali žarometa za kratki/dolgi svetlobni pramen;
The variation between the photometric values measured on each sample before and after the test shall not exceed 10 % including the tolerances of the photometric procedure.
Fotometrične vrednosti, izmerjene pri vsakem vzorcu pred preskusom in po njem, se ob upoštevanju dovoljenih odstopanj fotometričnega postopka ne smejo razlikovati za več kot deset odstotkov.
Resistance to atmospheric and chemical agents
Odpornost proti okoljskim in kemičnim dejavnikom
Resistance to atmospheric agents
Odpornost proti okoljskim dejavnikom
The samples shall be sprayed with distilled water of conductivity lower than 1 mS/m at a temperature of 23 °C ± 5 °C, in accordance with the following cycle:
Vzorce je treba škropiti z destilirano vodo s prevodnostjo, nižjo od 1 mS/m, pri temperaturi 23 °C ± 5 °C po naslednjem ciklu:
spraying 5 minutes;
škropljenje 5 minut;
drying 25 minutes.
sušenje 25 minut.
Resistance to chemical agents
Odpornost proti kemičnim dejavnikom
After the test described in paragraph 2.2.1 above and the measurement described in paragraph 2.2.3.1 below have been carried out, the outer face of the said three samples shall be treated as described in paragraph 2.2.2.2 with the mixture defined in paragraph 2.2.2.1 below.
Po preskusu, opisanem v odstavku 2.2.1 zgoraj, in meritvi, opisani v odstavku 2.2.3.1 spodaj, je treba obdelati zunanjo površino navedenih treh vzorcev po postopku, opisanem v odstavku 2.2.2.2, z mešanico, določeno v odstavku 2.2.2.1. spodaj.
The test mixture shall be composed of 61,5 % n-heptane, 12,5 % toluene, 7,5 % ethyl tetrachloride, 12,5 % trichlorethylene and 6 % xylene (volume %).
Preskusna mešanica vsebuje 61,5 % n-heptana, 12,5 % toluena, 7,5 % etiltetraklorida, 12,5 % trikloretilena in 6 % ksilena (volumski odstotki).
Soak a piece of cotton cloth (as per ISO 105) until saturation with the mixture defined in paragraph 2.2.2.1 above and, within 10 seconds, apply it for 10 minutes to the outer face of the sample at a pressure of 50 N/cm2, corresponding to an effort of 100 N applied on a test surface of 14 × 14 mm.
Kos bombažnega blaga (po standardu ISO 105) se do nasičenja namoči v mešanico iz odstavka 2.2.2.1 zgoraj in nato prej kot v 10 sekundah za 10 minut pritisne na zunanjo površino vzorca s pritiskom 50 N/cm2, kar ustreza sili 100 N na preskusno površino velikosti 14 × 14 mm.
During this 10-minute period, the cloth pad shall be soaked again with the mixture so that the composition of the liquid applied is continuously identical with that of the test mixture prescribed.
Med temi 10 minutami se blago ponovno napoji z mešanico, da sestava nanesene tekočine ustreza predpisani preskusni mešanici med celotnim trajanjem preskusa.
During the period of application, it is permissible to compensate the pressure applied to the sample in order to prevent it from causing cracks.
Med pritiskanjem namočenega blaga na vzorec se lahko pritisk, ki deluje na vzorec, izravna, da se prepreči nastajanje razpok.
At the end of the application of the test mixture, the samples shall be dried in the open air and then washed with the solution described in paragraph 2.3 (Resistance to detergents) at 23 °C ± 5 °C.
Po nanašanju preskusne mešanice se morajo vzorci posušiti na zraku, nato pa oprati z raztopino iz odstavka 2.3 (odpornost proti čistilom) pri temperaturi 23 °C ± 5 °C.
Afterwards the samples shall be carefully rinsed with distilled water containing not more than 0,2 % impurities at 23 °C ± 5 °C and then wiped off with a soft cloth.
Nato je treba vzorce dobro sprati z destilirano vodo, ki pri temperaturi 23 °C ± 5 °C ne vsebuje več kot 0,2 odstotka primesi, in jih obrisati z mehko krpo.
After the test of resistance to atmospheric agents, the outer face of the samples shall be free from cracks, scratches, chipping and deformation, and the mean variation in transmission Δt = T2
Po preskusu odpornosti proti okoljskim dejavnikom ne sme biti na zunanji površini vzorca nobenih razpok, prask, oddrobljenih delov in deformacij, srednja vrednost spremembe stopnje prepuščanja svetlobe Δt = T2
T3– 2.2.3.1. After the test of resistance to atmospheric agents, the outer face of the samples shall be free from cracks, scratches, chipping and deformation, and the mean variation in transmission Δt = T2
T3– .2.3.1 Po preskusu odpornosti proti okoljskim dejavnikom ne sme biti na zunanji površini vzorca nobenih razpok, prask, oddrobljenih delov in deformacij, srednja vrednost spremembe stopnje prepuščanja svetlobe Δt = T2