The wave function of an electron of a hydrogen atom in the ground state takes the form ψ(r) = A e-r/r1, where A is a certain constant, r1 is the first Bohr radius. Find:
(a) the most probable distance between the electron and the nucleus;
(b) the mean value of modulus of the Coulomb force acting on the electron;
(c) the mean value of the potential energy of the electron in the field of the nucleus.
