Find the ratio of ionization energy of hydrogen-like lithium atom and Bohr's hydrogen atom.

Energy of an electron in ground state of Bohr's hydrogen-like atom is given by,E=−13.6Z2n2eVwhere Z = atomic number of the atom.The ionization energy of this atom is equal in magnitude to energy of ground state=E∞=13.6Z2⇒E∞LiE∞H=ZLi2ZH2=312=9