1. The problem statement, all variables and given/known data An electron with energy 10^3 MeV collides with a photon whose wavelength corresponds to the maximum wavelength of the 2.7-K cosmic background radiation. What is the maximum energy loss the electron can suffer as a result of the collision? What is the wavelength of the photon after this maximal collision? 2. Relevant equations 3. The attempt at a solution I need help starting this problem, if anyone can help me. Thanks.