Calculate the amount of energy not used to produce electricity when a photon of wavelength #1*10^-12m# hits sodium metal which has a work function of 2.3eV?
Here we're relating a few things: (1) the energy of the photon, and (2) the difference between the work function and that energy.
Above is the energy of the photon, now we're going to convert the work function joules, as such,
So, relating these two values to realize our differential:
This is fairly reasonable since a photon of that wavelength is probably gamma, ouch!