1. The problem statement, all variables and given/known data Calculate the de broglie wavelength (DBW) of an electron with kinetic energy 60 GeV. What percentage of an atom's diameter can it penetrate? 2. Relevant equations DBW = h/p p=mv 3. The attempt at a solution Basically I have an electron traveling at the speed of light. I arrived at this from its kinetic energy (60 GeV) and by using the relativistic K-energy equation. So I get it's de broglie wavelength fairly easily (I have this part done). The part I don't understand is the penetration. I guess I just need some guidance/equations. Any ideas?