1. The problem statement, all variables and given/known data Assume that the total energy E of an electron greatly exceeds its rest energy E0. If a photon has a wavelength equal to the de Broglie wavelength of the electron, what is the photon’s energy? Repeat the prob- lem assuming E = 2E0 for the electron. I need help with the first part of the problem--I included my answer to the second part in case it is relevant to the first. 2. Relevant equations de Broglie wavelength λ=h/p E^2 = p^2c^2 + m^2c^4 E=hf=hc/λ 3. The attempt at a solution Part one of the problem: Knowing that E>>Erest, I can use the mass-energy relation to show that E^2 = P^2c^2, such that E=pc. From this I know that p=E/c I used this to show that the energy of the photon must be equal to the energy of the electron as follows: λelectron = λphoton λelectron = h/p = h/(E/c) = hc/Eelectron λphoton = hc/Ephoton hc/Eelectron = hc/Ephoton ---> Eelectron = Ephoton From here all I can see is that there is an infinite number of solutions. I don't understand how to winnow my process down so that it yields only one solution. That said, I don't even know if my process is 100% correct. Part two of the problem: λ=h/pelectron=hc/Ephoton Ephoton=c/pelectron E^2 = p^2c^2 + E0^2 = (2Eo)^2 = 4Eo^2 3Eo^2 = p^2c^c p=√3 * (Eo)/c such that: Ephoton=c/pelectron = c/(√3 * (Eo)/c), all of which are constants that I know the values of and which give me a real answer. What say you all about the first part of the problem?