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Verifying Duane-Hunt Relation

  1. Oct 24, 2011 #1
    1. The problem statement, all variables and given/known data
    Just going over some practice questions, and one of them is:

    1. Verify the value of the constant, 1240, in the Duane-Hunt relation.

    2. Relevant equations
    E(eV) = 1240/lambda(nm)

    3. The attempt at a solution
    I know it is used as a quick method in finding how much energy is involved when a molecule absorbs a photon of light. I therefore know how to use it in a question. However, I'm stumped as to verifying the actual value of the constant. Any insight is appreciated!
  2. jcsd
  3. Oct 24, 2011 #2


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    Homework Helper
    Gold Member

    Look up the definition of Planck's constant, or more specifically what is called the "Planck relation" or the "Planck–Einstein equation". It relates the energy of a photon to the photon's frequency (or wavelength).

    A few other things you may need to know.

    • What is the speed of light in a vacuum (in [m/sec])?
    • What is Planck's constant (in [J sec])?
    • If you know the frequency of a photon, what is the photon's wavelength?
    • How many Joules are there in one electron-volt?
    • how many nanometers are there in a meter?
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