Absorption prob - why my way isn't correct?

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Discussion Overview

The discussion revolves around the energy transitions of a hydrogen electron when subjected to radiation and subsequent emission. Participants explore the calculations of energy differences between quantum levels, the relevance of Rydberg's formula, and the interpretation of emitted photon energy in relation to energy levels.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant describes their method of calculating energy differences using given wavelength and frequency, questioning why it differs from using Rydberg's formula.
  • Another participant challenges the correctness of calculating energy using frequency without further clarification.
  • Several participants suggest creating a diagram to visualize energy levels and transitions to aid understanding.
  • There is a discussion about the energy emitted during the electron's transition and its relation to the energy levels involved.
  • One participant asserts that the energy of the emitted photon corresponds to the difference between the two levels, not involving the ground state.
  • Another participant expresses confusion over the calculations, indicating a discrepancy in expected results.
  • Participants acknowledge that the correct energy difference should be derived from the emitted photon, leading to a realization about the calculations.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the initial calculation method, with some supporting the use of Rydberg's formula while others argue against it. The discussion reflects uncertainty regarding the correct approach to determine energy differences.

Contextual Notes

There are unresolved aspects regarding the assumptions made in the calculations and the definitions of energy levels. The relationship between the emitted photon energy and the specific energy levels involved remains a point of contention.

Who May Find This Useful

This discussion may be useful for students studying quantum mechanics, particularly those grappling with concepts of energy transitions in hydrogen atoms and the application of relevant formulas in calculations.

assaftolko
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Homework Statement


A hydrogen electron is at its ground level when it's radiated in wave length of 94.92 nm. As a result it arrises to level a. then emission occures with frequency of 2.34*10^14 Hz and the electron falls to level b. What's the energy difference between the 2 levels

Homework Equations


E=hv, c=λv

The Attempt at a Solution


I found E1 using λ1 that's given to me, E2 using v2 given to me and substracted E2 from E1. Why isn't this way correct and you have to use rydberg's formula? whay the 2 don't give the same result? I got 1.94*10^-18 J
 
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You don't have to use Rydberg's formula, but is
assaftolko said:
I found [...] E2 using v2
correct?
 
Why not? Thought so...
 
assaftolko said:
Why not? Thought so...

Make a diagram with the energy levels and the transitions, you will see.
 
Im sorry i don't quite get how to understand my mistake...
 
Ok, let's try another approach. Can you tell me what happens in the last step of the process?
 
DrClaude said:
Ok, let's try another approach. Can you tell me what happens in the last step of the process?

Energy is emitted from the electron so it "drops" to a lower energy level, closer to the ground level than it was at first after it arrived to level a
 
And to what does the energy of the emitted photon correspond?
 
DrClaude said:
And to what does the energy of the emitted photon correspond?

to hv... so what you're saying is that this energy is not the energy of level b with respect to the ground level, but with respect to level a?
 
  • #10
Exactly! You get directly the the difference in energy between the levels from the emitted photon. The difference between the ground state and level a is actually irrelevant here.
 
  • #11
DrClaude said:
Exactly! You get directly the the difference in energy between the levels from the emitted photon. The difference between the ground state and level a is actually irrelevant here.

that's weird because you still don't get the correct answer - which should be 1.55*10^-19 J

Oh **** yes it does... Oh man :/

Thanks!
 
  • #12
You're welcome!
 

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