Calculate the de Broglie wavelengths of an electron with energy 120 eV ...
lambda = h\p where p = sqrt(2*Me*E)
The Attempt at a Solution
Then sub into equation and I get 1.1E-10m for the wavelength, which is the answer quoted.
The question that concerns me is why can you not use E=hf, where rearranged gives lambda=(hc/E) which gives
a different answer...