Bohr Model


by whiteshado
Tags: bohr, model
whiteshado
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#1
May5-05, 08:41 PM
P: 33
could i get help or a formula for this question please

Use the Energy Levels for Hydrogen to calculate the wavelength corresponding to the following electron transition
Transition Energy in ev's Emitted wavelengths in m
2->1______ ________x10______
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quasar987
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#2
May5-05, 08:47 PM
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Here's a formula you can use after you've discovered how many energy is contained in the photon emited during the transition of the electron

[tex]E=hf[/tex]

where f is the frequency of the photon. How are frequency and wavelenght related?
whiteshado
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#3
May5-05, 08:51 PM
P: 33
taht is the question im as stumped as you are tahts all the info i have i had taht equation though it doesnt haev wavelength also how do i find the energy?

what
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#4
May5-05, 08:58 PM
P: 92

Bohr Model


I dont think quasar is stumped, i think he was asking you a question which has an answer. The energy should be a given, or predicted by the bohr model. Think back to waves what other equation relates wavelength and frequency.
whiteshado
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#5
May5-05, 09:03 PM
P: 33
well speed of sound divided by wavelength =frequency
whiteshado
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#6
May5-05, 09:05 PM
P: 33
is taht what you were asking for?
whozum
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#7
May5-05, 09:07 PM
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A photon travels at the speed of _____
whiteshado
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#8
May5-05, 09:13 PM
P: 33
hf is the energy of the radiated photons

thats all i got
whozum
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#9
May5-05, 09:18 PM
P: 2,223
Ok, a photon travels at the speed of light. If its energy is given by hF, then the relationship


c = (Frequency)(Wavelength) should give you its wavelength. All you ahve to do is find the energy drop from 2->1 and solve this equation and plug it into the E = hF one.
quasar987
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#10
May5-05, 09:33 PM
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Quote Quote by whiteshado
well speed of sound divided by wavelength =frequency
This is also true for light. Light is a wave too, and a "photon" is only a fancy name we give to "little chuncks" (quanta!) of light.

So speed of light divided by wavelength =frequency.
whiteshado
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#11
May5-05, 09:42 PM
P: 33
k so correct me if im wrong 2-1 =-13.6 evs and w =-13.6evs/6.63e-34

?
quasar987
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#12
May5-05, 09:52 PM
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Quote Quote by whiteshado
k so correct me if im wrong 2-1 =-13.6 evs and w =-13.6evs/6.63e-34

?
-13.6 eV is the energy the electron has when it is in state n=1.

You're looking for the energy it has lost in going from state n=2 to state n=1, hence you want the difference between the energy of n=1 and the energy of n=2:

[tex]\Delta E = E_f - E_i[/tex]
whiteshado
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#13
May5-05, 09:55 PM
P: 33
12.2? is that it? nope it was 10.2
quasar987
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#14
May5-05, 09:56 PM
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yeah.

-----------
whiteshado
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#15
May5-05, 10:37 PM
P: 33
hmm i got 1.15e53
10.2/1.6e-19/6.63e-34
its not right thought i think i missed soemthing
wait is this is my freqwuancy correcT?
quasar987
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#16
May5-05, 10:57 PM
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1 kg = 1000 grams, so 2.3 kg = 2.3*1000 = 2300 grams.

Same thing here: 1 eV = 1.6*10^19 J, so 12.2 eV = 12.2*1.6*10^-19 J.
whiteshado
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#17
May5-05, 11:01 PM
P: 33
ahhh i devided instead of multiplying
jtbell
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#18
May6-05, 12:39 AM
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In problems like this it's easier to use Planck's constant in eV instead of joules:

[tex]\frac {10.2 eV} {4.14 \times 10^{-15} eV \cdot seconds} [/tex]


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