Cov Lus Nug Piv Txwv Sib Tham Txog Lub Tswv Yim ntawm Photons
Cov photons yog cov khoom me me uas tsim lub hauv paus ntawm txoj kev xav ntawm lub teeb quantum. Raws li lub teeb quantum, lub photon nqa lub pob ntawm lub zog ncaj qha cuam tshuam nrog nws qhov zaus. Lub tswv yim no tau qhia thawj zaug los ntawm Albert Einstein hauv xyoo 1905. Hauv tsab xov xwm no, peb yuav tham txog ntau qhov piv txwv thiab kev sib tham txog photons kom meej meej peb txoj kev nkag siab txog cov ncauj lus no.
Kev Nkag Siab Yooj Yim ntawm Photons
Cov photons yog cov khoom me me, lossis quanta, ntawm hluav taws xob electromagnetic. Hauv kev tshawb fawb quantum, cov photons tsis muaj qhov hnyav so tab sis muaj lub zog thiab momentum. Lub zog ntawm photon tuaj yeem suav los ntawm kev siv cov qauv tsim los ntawm Max Planck:
\[ E = hf \]
Qhov twg:
- \( E \) yog lub zog photon
- \( h \) yog Planck tus nqi tas mus li ( \( 6.626 \times 10^{-34} \) Js)
- \( f \) yog zaus ntawm lub teeb
Qhov kev sib raug zoo ntawm lub zog photon thiab wavelength {\(\lambda\)} tuaj yeem qhia los ntawm cov qauv hauv qab no:
\[ E = \frac{hc}{\lambda} \]
Qhov twg:
- \( c \) yog qhov ceev ntawm lub teeb hauv lub tshuab nqus tsev \( (3 \times 10^8 \) m/s)
Cov Lus Nug Piv Txwv thiab Kev Sib Tham
Lo lus nug 1: Xam lub zog photon
Lus Nug: Ib lub photon muaj qhov ntev ntawm 500 nm. Xam lub zog ntawm lub photon hauv joules.
Kev Sib Tham:
Ua ntej, peb hloov qhov wavelength ntawm nanometers mus rau meters.
\[ 500 \ \text{nm} = 500 \times 10^{-9} \ \text{m} \]
Siv cov qauv zog photon:
\[ E = \frac{hc}{\lambda} \]
Sau cov nqi ntawm Planck qhov tsis tu ncua (\( h = 6.626 \times 10^{-34} \) Js) thiab qhov ceev ntawm lub teeb \( c = 3 \times 10^8 \ \text{m/s} \):
\[ E = \frac{(6.626 \times 10^{-34} \ \text{Js}) \times (3 \times 10^8 \ \text{m/s})}{500 \times 10^{-9} \ \text{m}} \]
\[ E = \frac{1.9878 \times 10^{-25}}{500 \times 10^{-9}} \]
\[ E = 3.976 \times 10^{-19} \ \text{J} \]
Yog li, lub zog ntawm photon yog 3.976 joules (10-19) lub zog.
Lo Lus Nug 2: Xam Qhov Zaus ntawm Lub Zog Photon
Lus Nug: Yog tias ib lub photon muaj lub zog ntawm ∑(2.5 \times 10^{-19} \) joules, qhov zaus ntawm lub teeb uas photon muaj yog dab tsi?
Kev Sib Tham:
Peb siv cov qauv yooj yim ntawm lub zog photon:
\[ E = hf \]
Peb cais qhov zaus \( f \):
\[ f = \frac{E}{h} \]
Sau cov nqi ntawm lub zog \(E \) thiab Planck's tas mus li \(h \):
\[ f = \frac{2.5 \times 10^{-19} \ \text{J}}{6.626 \times 10^{-34} \ \text{Js}} \]
\[ f = 3.77 \times 10^{14} \ \text{Hz} \]
Yog li, qhov zaus ntawm lub teeb yog \(3.77 \times 10^{14} \ \text{Hz} \).
Lo lus nug 3: Cov nyhuv photoelectric
Lus Nug: Hauv kev sim ua kom pom tseeb ntawm photoelectric, ib lub photon nrog lub zog 4.0 eV ntaus rau ntawm qhov chaw hlau thiab tso tawm ib lub electron. Yog tias lub luag haujlwm ua haujlwm ntawm cov hlau yog 2.5 eV, xam lub zog kinetic siab tshaj plaws ntawm lub electron uas tso tawm.
Kev Sib Tham:
Lub zog photon \(E \) yog muab rau hauv electronvolts (eV). Peb tuaj yeem siv tus nqi no ncaj qha vim tias qhov kev ua haujlwm kuj yog nyob rau hauv eV.
Lub luag haujlwm ua haujlwm (\(W \)) yog lub zog tsawg kawg nkaus uas xav tau los tshem tawm ib lub electron ntawm qhov chaw hlau. Lub zog kinetic siab tshaj plaws (\(KE \)) ntawm ib lub electron yog suav ua qhov sib txawv ntawm lub zog photon thiab lub luag haujlwm ua haujlwm:
\[ KE = E – W \]
Sau cov nqi ntawm lub zog photon \(E = 4.0 \ \text{eV} \) thiab lub luag haujlwm ua haujlwm \(W = 2.5 \ \text{eV} \):
\[ KE = 4.0 \text{eV} – 2.5 \text{eV} \]
\[ KE = 1.5 \ \text{eV} \]
Yog li, lub zog kinetic siab tshaj plaws ntawm cov electron tso tawm yog 1.5 eV.
Lo lus nug 4: Wavelength Los ntawm Zaus
Lo lus nug: Lub wavelength ntawm ib lub photon uas muaj zaus ntawm 6 \times 10^{14} \ \text{Hz} \) yog dab tsi?
Kev Sib Tham:
Siv kev sib raug zoo ntawm qhov ceev ntawm lub teeb, zaus, thiab wavelength:
\[ c = \lambda f \]
Peb cais qhov wavelength \( \lambda \):
\[ \lambda = \frac{c}{f} \]
Sau cov nqi rau qhov ceev ntawm lub teeb \(c = 3 \times 10^8 \ \text{m/s} \) thiab zaus \(f = 6 \times 10^{14} \ \text{Hz} \):
\[ \lambda = \frac{3 \times 10^8 \ \text{m/s}}{6 \times 10^{14} \ \text{Hz}} \]
\[ \lambda = 5 \times 10^{-7} \ \text{m} \]
\[ \lambda = 500 \ \text{nm} \]
Yog li, qhov wavelength ntawm photon yog 500 nm.
Lo lus nug 5: Lub zog photon hauv Spectrum
Lus Nug: Ib lub photon hauv lub spectrum ultraviolet muaj qhov ntev ntawm 150 nm. Xam lub zog ntawm lub photon hauv joules thiab electronvolts.
Kev Sib Tham:
Ua ntej, hloov qhov wavelength mus rau meters:
\[ 150 \ \text{nm} = 150 \times 10^{-9} \ \text{m} \]
Xam lub zog photon hauv joules:
\[ E = \frac{hc}{\lambda} \]
Sau cov nqi:
\[ E = \frac{(6.626 \times 10^{-34} \ \text{Js}) \times (3 \times 10^8 \ \text{m/s})}{150 \times 10^{-9} \ \text{m}} \]
\[ E = \frac{1.9878 \times 10^{-25}}{150 \times 10^{-9}} \]
\[ E = 1.3252 \times 10^{-18} \ \text{J} \]
Yuav hloov joules mus rau electronvolts, peb siv 1eV = 1.602 \times 10^{-19} \) J:
\[ E \ (\text{eV}) = \frac{1.3252 \times 10^{-18} \ \text{J}}{1.602 \times 10^{-19} \ \text{J/eV}} \]
\[E \(\text{eV}) = 8.27 \text{eV} \]
Yog li, lub zog ntawm lub photon ultraviolet yog ∑(1.3252 \times 10^{-18} \ \text{J} \) lossis 8.27 eV.
Xaus
Los ntawm ntau yam piv txwv teeb meem thiab kev sib tham saum toj no, peb tau nkag siab tob dua txog cov yam ntxwv thiab kev xam suav ntsig txog photons. Qhov no suav nrog kev xam lub zog raws li wavelength thiab zaus, nrog rau kev siv lub tswv yim photon hauv cov nyhuv photoelectric. Kev nkag siab txog lub tswv yim photon tseem ceeb tsis yog hauv kev xav xwb tab sis kuj tseem ceeb hauv ntau yam kev siv thev naus laus zis niaj hnub xws li photovoltaics, lasers, thiab lub teeb sensors. Yog tias xyaum txaus, kev nkag siab txog cov tswv yim no yuav yooj yim dua thiab nkag siab ntau dua.
