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Homework Help: Atomic clock: energy between two levels

  1. Jan 26, 2015 #1
    1. The problem statement, all variables and given/known data
    With the atomic clock a second is defined as the time it takes for EM radiation to oscillate 9192631770 times, which equals the energy gap between two energy levels of a caesium-133 atom. Note: it's a translation and the term used with the oscillation is "oscillation periods"

    2. Relevant equations
    Calculate the energy difference (in eV)

    3. The attempt at a solution

    At first I took the expression "oscillation periods" to mean that I had to use the T=1/f relation and insert it in the E=hf equation. However since T is in seconds and f means turns or oscillations, I went with f=9192631770.

    So, I have:
    E = hf
    = 6.626*10^(-34) Js * 9192631770 /s
    = 6.091*10^(-24) J
    = 3.8 * 10^(-5) eV

    I just hope to check whether I made the right assumptions and conversions, thank you.
  2. jcsd
  3. Jan 26, 2015 #2


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    Science Advisor
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    Gold Member

    Your answer matches the one here: http://hyperphysics.phy-astr.gsu.edu/hbase/acloc.html
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