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Zorluk: OrtaEnergy Levels and Atomic Spectra

An electron inside an excited atom drops from an energy state of 1.20 eV-1.20\text{ eV} to a lower energy state of 4.50 eV-4.50\text{ eV}. What is the frequency of the emitted electromagnetic radiation, in units of 1014 Hz10^{14}\text{ Hz}? (Take Planck's constant h=6.6×1034 J sh = 6.6 \times 10^{-34}\text{ J s} and 1 eV=1.6×1019 J1\text{ eV} = 1.6 \times 10^{-19}\text{ J})

Cevap: 8 10^14 Hz

Cevap

The frequency of the emitted electromagnetic radiation is 8.0×1014 Hz8.0 \times 10^{14}\text{ Hz} (or 8.0 in units of 1014 Hz10^{14}\text{ Hz}).
The energy of the photon emitted during a downward transition between discrete atomic energy levels is equal to the energy difference between the initial and final states. Calculating ΔE=1.20 eV(4.50 eV)=3.30 eV\Delta E = -1.20\text{ eV} - (-4.50\text{ eV}) = 3.30\text{ eV}, converting to Joules gives 3.30×1.6×1019 J=5.28×1019 J3.30 \times 1.6 \times 10^{-19}\text{ J} = 5.28 \times 10^{-19}\text{ J}. Dividing this energy by Planck's constant 6.6×1034 J s6.6 \times 10^{-34}\text{ J s} yields a frequency of 8.0×1014 Hz8.0 \times 10^{14}\text{ Hz}.

Adım Adım Çözüm

1
Determine the energy of the emitted photon in electron-volts
\Delta E = 3.30\text{ eV}
The energy of the emitted photon equals the difference between the upper and lower atomic energy levels: ΔE=1.20 eV(4.50 eV)=3.30 eV\Delta E = -1.20\text{ eV} - (-4.50\text{ eV}) = 3.30\text{ eV}.
2
Convert photon energy from electron-volts to Joules
\Delta E = 5.28 \times 10^{-19}\text{ J}
Since Planck's constant is given in SI units (J s), energy must be converted to Joules using 1 eV=1.6×1019 J1\text{ eV} = 1.6 \times 10^{-19}\text{ J}.
3
Calculate photon frequency using Planck's relation
f = 8.0 \times 10^{14}\text{ Hz}
Applying f=ΔEh=5.28×1019 J6.6×1034 J sf = \frac{\Delta E}{h} = \frac{5.28 \times 10^{-19}\text{ J}}{6.6 \times 10^{-34}\text{ J s}} yields 8.0×1014 Hz8.0 \times 10^{14}\text{ Hz}.

Anahtar Kavram

Photon Emission and Energy Level Transitions
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