Repeat Problem 64(a), this time assuming the electron is ultra-relativistic ( E ≈ pc ). Is the assumption justified?
(a) Assuming that the electron moves at nonrelativistic speeds, find the ground-state energy in mega-electronvolts of an electron confined to a one-dimensional box of length 5.0 fm (the approximate diameter of the 4He nucleus). (The electron actually does move at relativistic speeds. See Problem 80.)