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Calculating the width of the box for a particle in a box

  • #1

Homework Statement



A ruby laser emits light of wavelength 694.3 nm. If this light is due to the transition from n=2 to n=1 state of the electron in a box, what is the width of the box?

Homework Equations



K=2pi/Lambda
kL=npi

The Attempt at a Solution


Thinkin about the problem, i have calculated K as shown in my formula to be 9049669 but when i use this k to find L then i end up with 694.3 again. I dont know if this is the answer or if this is a really big mistake???
 

Answers and Replies

  • #2
fzero
Science Advisor
Homework Helper
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The K and k in those equations are not the same. [tex]K = 2\pi/\lambda[/tex] is the wavenumber of the emitted photon. [tex] k = n\pi/L[/tex] are the wavenumbers of the electron wavefunctions. You need to compute the difference in electron energy levels and equate that to the energy of the photon.
 

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