Cov Lus Nug Piv Txwv Sib Tham Txog Qhov Teeb Meem Photoelectric
Qhov teebmeem photoelectric yog ib qho xwm txheej uas piav qhia txog kev tso tawm ntawm cov electrons los ntawm qhov chaw ntawm cov khoom siv thaum lub teeb lossis hluav taws xob electromagnetic ntaus nws. Kev tshawb fawb uas Albert Einstein tau ua thaum ntxov xyoo pua 20th tau ua lub luag haujlwm tseem ceeb hauv kev piav qhia txog qhov xwm txheej no thiab ua rau kev lees txais ntawm txoj kev xav quantum ntawm lub teeb. Tsab xov xwm no yuav tham txog ntau qhov teeb meem piv txwv ntsig txog qhov teebmeem photoelectric nrog rau kev piav qhia ntxaws ntxaws ntawm lawv cov kev daws teeb meem.
Txoj Kev Tshawb Fawb Tseem Ceeb
Ua ntej peb mus rau cov teeb meem piv txwv, cia peb rov xyuas qee lub ntsiab lus tseem ceeb ntsig txog cov teebmeem photoelectric:
1. Lub zog photon: Lub zog ntawm photon yog muab los ntawm kab zauv \( E = h \nu \), qhov twg \( h \) yog Planck's constant (\( h \approx 6.626 \times 10^{-34} \) Js) thiab \( \nu \) yog zaus ntawm lub teeb.
2. Kev ua haujlwm (\( \phi \)): Kev ua haujlwm yog lub zog tsawg kawg nkaus uas xav tau los tshem tawm cov electrons ntawm qhov chaw ntawm cov khoom.
3. Lub zog Kinetic ntawm cov electrons: Cov electrons uas tso tawm muaj lub zog kinetic uas muab los ntawm kab zauv \( KE = h \nu - \phi \).
Piv txwv lus nug 1
Lo lus nug
Ib daim hlau muaj lub luag haujlwm ua haujlwm ntawm \(4.5 \) eV. Lub teeb nrog lub wavelength ntawm \(200 \) nm ci ntsa iab rau ntawm daim ntawv. Txheeb xyuas:
1. Lub zog ntawm cov photon uas lub electron nqus tau.
2. Cov electrons puas yuav raug tso tawm ntawm qhov chaw hlau?
3. Yog tias yog, lub zog kinetic siab tshaj plaws ntawm cov electrons uas tso tawm yog dab tsi?
Kev daws teeb meem
1. Xam lub zog photon (\( E \))
\[
E = \frac{hc}{\lambda}
\]
Qhov twg \(h \) yog Planck tus nqi tas mus li, \(c \) yog qhov ceev ntawm lub teeb (c \approx 3 \times 10^8 \) m/s), thiab \(lambda \) yog qhov wavelength ntawm lub teeb.
\[
E = \frac{6.626 \times 10^{-34} \text{ Js} \times 3 \times 10^8 \text{ m/s}}{200 \times 10^{-9} \text{ m}}
\]
\[
E = \frac{1.9878 \times 10^{-25} \text{ Js}}{200 \times 10^{-9} \text{ m}}
\]
\[
E = 9.939 \times 10^{-19} \text{ J}
\]
Yuav hloov mus rau eV, siv \( 1 \text{ eV} = 1.602 \times 10^{-19} \text{ J} \).
\[
E = \frac{9.939 \times 10^{-19} \text{ J}}{1.602 \times 10^{-19} \text{ J/eV}}
\]
\[
E \approx 6.2 \text{ eV}
\]
2. Xyuas seb cov electrons puas yuav raug tso tawm
Vim tias lub zog photon (6.2 eV) loj dua li qhov ua haujlwm ua haujlwm (4.5 eV), lub electron yuav raug tso tawm.
3. Xam lub zog kinetic siab tshaj plaws ntawm cov electrons
\[
KE = E – \phi = 6.2 \text{eV} – 4.5 \text{eV} = 1.7 \text{eV}
\]
Piv txwv lus nug 2
Lo lus nug
Lub teeb nrog lub zaus ntawm \( 1.2 \times 10^{15} \) Hz ci ntsa iab rau ntawm qhov chaw hlau uas muaj lub luag haujlwm ua haujlwm ntawm \( 3 \) eV. Txheeb xyuas:
1. Lub zog ntawm cov photon uas lub electron nqus tau.
2. Cov electrons puas yuav raug tso tawm ntawm qhov chaw hlau?
3. Yog tias yog, lub zog kinetic siab tshaj plaws ntawm cov electrons uas tso tawm yog dab tsi?
Kev daws teeb meem
1. Xam lub zog photon (\( E \))
\[
E = h \nu = 6.626 \times 10^{-34} \text{ Js} \times 1.2 \times 10^{15} \text{ Hz}
\]
\[
E = 7.9512 \times 10^{-19} \text{ J}
\]
Kev Hloov Mus Rau eV:
\[
E = \frac{7.9512 \times 10^{-19} \text{ J}}{1.602 \times 10^{-19} \text{ J/eV}}
\]
\[
E \approx 4.97 \text{ eV}
\]
2. Xyuas seb cov electrons puas yuav raug tso tawm
Vim tias lub zog photon (4.97 eV) loj dua li qhov ua haujlwm ua haujlwm (3 eV), lub electron yuav raug tso tawm.
3. Xam lub zog kinetic siab tshaj plaws ntawm cov electrons
\[
KE = E – \phi = 4.97 \text{eV} – 3 \text{eV} = 1.97 \text{eV}
\]
Piv txwv lus nug 3
Lo lus nug
Lub teeb UV nrog lub wavelength ntawm \(120 \) nm ntaus rau ntawm qhov chaw hlau uas muaj lub luag haujlwm ua haujlwm ntawm \(2.2 \) eV. Xam:
1. Lub zog photon hauv eV.
2. Cov electrons puas yuav raug tso tawm ntawm qhov chaw hlau?
3. Yog tias yog, lub zog kinetic siab tshaj plaws ntawm cov electrons uas tso tawm yog dab tsi?
Kev daws teeb meem
1. Xam lub zog photon (\( E \))
\[
E = \frac{hc}{\lambda}
\]
\[
E = \frac{6.626 \times 10^{-34} \text{ Js} \times 3 \times 10^8 \text{ m/s}}{120 \times 10^{-9} \text{ m}}
\]
\[
E = \frac{1.9878 \times 10^{-25} \text{ Js}}{120 \times 10^{-9} \text{ m}}
\]
\[
E = 1.6565 \times 10^{-18} \text{ J}
\]
Kev Hloov Mus Rau eV:
\[
E = \frac{1.6565 \times 10^{-18} \text{ J}}{1.602 \times 10^{-19} \text{ J/eV}}
\]
\[
E \approx 10.34 \text{ eV}
\]
2. Xyuas seb cov electrons puas yuav raug tso tawm
Vim tias lub zog photon (10.34 eV) loj dua li qhov ua haujlwm ua haujlwm (2.2 eV), lub electron yuav raug tso tawm.
3. Xam lub zog kinetic siab tshaj plaws ntawm cov electrons
\[
KE = E – \phi = 10.34 \text{eV} – 2.2 \text{eV} = 8.14 \text{eV}
\]
Xaus
Qhov teeb meem ntawm cov teebmeem photoelectric tuaj yeem piav qhia los ntawm ntau yam teeb meem piv txwv uas peb xam lub zog ntawm photon, xyuas seb puas muaj peev xwm tso tawm electron, thiab ntsuas lub zog kinetic siab tshaj plaws ntawm cov electron uas tso tawm. Thaum daws txhua qhov teeb meem, peb yuav tsum ceev faj nrog cov chav nyob thiab kev hloov pauv ntawm cov chav nyob (piv txwv li, los ntawm joules mus rau electronvolts). Kev nkag siab zoo thiab kev xyaum ua kom raug yuav pab peb paub txog cov ntsiab lus tseem ceeb ntawm cov teebmeem photoelectric, uas yog lub hauv paus tseem ceeb ntawm quantum physics.
