1.19 Consider a one-electron atom (or ion), the nucleus of which contains A nucleons (Z protons and N = A - Z neutrons). The mass of that nucleus is given approximately by MAMp, where Mp 1.67 x 10-27 kg is the proton mass. Using this value of M, obtain the relative correction AE/E to the Bohr energy levels due to the finite nuclear mass for the case of atomic hydrogen (A = 1, Z = 1), deuterium (A = 2, Z = 1), tritium (A = 3, Z = 1) and He* (A = 4, Z = 2).