Show that the differential cross section for the photoelectric effect in which an electron in the ground state of hydrogen is ejected when the atom absorbs a photon is given by h ky(e k = 320 mw do [(1/a)+qr where q ki kf. assume the ejected electron is sufficiently energetic that the wave function for the electron can be taken to be the plane wave ekr (rlk) v where p hk, is the momentum of the electron and ak, is the momentum of the incident photon. suggestion: the cross section is the transition rate divided by the incident photon flux, which is equal to c/v in the box normalization used in this chapter.