Lub teeb taug kev los ntawm lub tshuab nqus tsev txav raws nraim 299, 792, 458 meters (983, 571, 056 ko taw) ib ob. Qhov ntawd yog hais txog 186, 282 mais ib pliag - ib qho tas li universal tas li Ib lub cev tsis tu ncua, qee zaum tseem ceeb lub cev tsis tu ncua lossis universal tas li, yog lub cev ntau uas feem ntau ntseeg tau tias yog ob qho tib si thoob ntiaj teb hauv qhov xwm txheej thiab muaj nuj nqis tas li hauv lub sijhawm. … Txij li thaum lub Tsib Hlis 2019, tag nrho cov SI hauv paus units tau raug txhais raws li lub cev tsis tu ncua. https://en.wikipedia.org › wiki › Physical_constant
Lub cev tsis tu ncua - Wikipedia
paub hauv qhov sib npaug thiab luv luv li "c," lossis qhov ceev ntawm lub teeb.
Vim li cas lub teeb teb yog dab tsi?
Lub teeb mus ntawm kwv yees li 300, 000 km / thib obhauv lub tshuab nqus tsev, uas muaj qhov ntsuas pom ntawm 1.0, tab sis nws qeeb mus rau 225, 000 km / thib ob hauv dej (refractive index ntawm 1.3; saib daim duab 2) thiab 200, 000 kilometers ib ob nyob rau hauv iav (refractive index ntawm 1.5).
Yuav ua li cas mus nrog qhov nrawm nrawm?
Nyob rau hauv txoj kev xav no, lub teeb tau piav qhia los ntawm qhov tseem ceeb excitations (los yog quanta) ntawm electromagnetic teb, hu ua photons. Nyob rau hauv QED, photons yog massless hais thiab yog li, raws li tshwj xeeb relativity, lawv mus ntawm ceev ntawm lub teeb nyob rau hauv lub nqus tsev vacuum.
Vim li cas lub teeb nrawm tas li?
Nws yog ib qho yooj yim postulate ntawm txoj kev xav ntawm kev sib raug zoo uas qhov ceev ntawm lub teeb yog tas li. Qhov no tuaj yeem tawg ua ob ntu: nrawm ntawm lub teeb yog ywj pheej ntawm kev txav ntawm tus neeg soj ntsuam. Qhov ceev ntawm lub teeb tsis txawv raws sijhawm lossis qhov chaw.
Vim li cas ntawm lub teeb chemistry?
4. Hauv lub tshuab nqus tsev, txhua hom hluav taws xob hluav taws xob hluav taws xob-txawm tias microwaves, pom lub teeb, lossis gamma rays-mus ncig ntawm lub teeb nrawm (c), uas dhau los ua qhov tseem ceeb ntawm lub cev tsis tu ncua nrog tus nqi ntawm 2.99792458 × 108 m/s (kwv yees 3.00 × 108 m/s lossis 1.86 × 10 5mi/s).
