A 120nm photon strikes an electron in a head on collison causing the elctron to be moved in the forward direction and the photon to rebound directly back. A. Calculate the inital speed of the Electron after colison. B. Calculate the wavelength of the rebounding Photon. E=H/f E = W+Ek p= H/Wavelength Givens: C= 3.0x10^8m/s H = 6.63x10^-34J*S Although the problem being linear simplifies it a bit, i still had trouble with it. so here i go. Equation one. E(prime)= HC/Wavelength - 1/2mv^2 HC/Wavelength(prime) = HC/Wavelength - 1/2mv^2 Equation two. HC/Wavelength(prime) = -HC/Wavelength + Cmv Therefore HC/Wavelength - 1/2mv^2 = -HC/Wavelength + Cmv Rearranged this makes: (some parts already calculated for simplicity sake) 3.32x10^-8J / (c)(m^2)(2) = v+v^2 3.32x10^-8J / 4.98x10^-52 = v+v^2 6.67x10^59 = v+v^2 Squareroot(6.67x10^59/2) = v 5.77x10^29 = v But this answer must be wrong since its going way faster then the speed of light. maybe some clarification on where i went wrong or if i made some silly math error would be awesome.