1. The problem statement, all variables and given/known data A step potential is defined by: V(x) = 0 ( for for x <0 ) and V(x) = V0 ( for x >0 ). Hence the step occurs at the origin. Suggest a real physical situation, that might correspond to this idealized problem 2. Relevant equations None needed. 3. The attempt at a solution Looks simple, but I can't think of anything that this might correspond to. I was thinking about an electron being bound to an atom, and the step potential is like the ionizing potential, but since V0 goes from x = 0 to x = infinity, there can't be such potential... Or maybe a highly negative charged plate, so an electron moving at the positive direction would not pass through, but it is free to move in a negative direction ( 1D situation ). Does anybody have any ideas?