The ground state energy of hydrogen atom is $$-$$ 13.6 eV. When its electron is in the first excited state, its excitation energy is

If M(A; Z), M_p and M_n denote the masses of the nucleus $${}_Z^AX,$$ proton and neutron respectively in units of u (1 u = 931.5 MeV/c²) and BE represents its bonding energy in MeV, then

The total energy of electron in the ground state of hydrogen atom is $$-$$ 13.6 eV. The kinetic energy of an electron in the first excited state is

If the nucleus $${}_{13}^{27}Al$$ has a nuclear radius of about 3.6 fm, them $${}_{32}^{125}Te$$ would have its radius approximately as