1. The problem statement, all variables and given/known data One could imagine that beta decay was due to a electron initially inside the nucleus and than leaving it. Proof by using Heisenberg uncertainty principle that this is not possible. There is a hint which says you can use energy spectra and values for the energy of beta particles. 2. Relevant equations 3. The attempt at a solution I think this has something to do with the energy being continuos and that the beta particles can have very different energies but I really have no idea how to proof this.