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    What is the energy (in KJmol^-1) of X-ray photons with a wavelength of 100pm?

    I tried to use E=hv and c-v*wavelength and rearrange but i dont get the right answer

    Correct answer:1.20 x10^6

    I'm using w for wavelength here, since there is no lambda!

    If v=fw and v=c,
    c=fw, and f= c/w
    Then you should be able to use E=hf and get the energy.
    I'm not sure why there's the kJ/mol there though - maybe that's something to do with the context of the question.
    That's how I'd work it out anyway, good luck!
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