The ratio of ionization energy of Bohr's hydrogen atom and Bohr's hydrogen-like lithium atom is

Options

A. `1:1`
B. `1:3`
C. `1:9`
D. None of these

Answer

C

Explanation

Energy of an electron in ground state of an atom (Bohr's hydrogen-lke atom) is given as
`E =- 13.6Z^(2)eV(Z =` atomic number of the atom)
`rArr E_("ionisation") = 13.6 Z^(2)`
`rArr ((E_(ion))_(H))/((E_(ion))_(Li)) = ((Z_(H))/(Z_(Li)))^(2) = ((1)/(3))^(2) = (1)/(9)`