1. The problem statement, all variables and given/known data I have to figure how many beta particles are released and how much energy is released as gamma rays in the complete decay of 1000 atoms of (12/5) Boron. 2. Relevant equations Mass of one boron atom is 10.811 g. I think we may be able to use E = mc^2 somehow but I'm not sure. 3. The attempt at a solution The answer the book gives is that 1000 beta particles are released and 88 MeV of energy is released as gamma rays. The first seems obvious because (12/5) boron decays into (12/6) C + an electron. So if you have 1000 atoms you will have 1000 electrons / beta particles. The second I'm not so sure of. How can you calculate the energy released as gamma rays from just this information?