The ionization potential for hydrogen atom is `13.6 eV`, the ionization potential for `He^(+)` is

Options

A. 54.4 eV
B. 6.8 eV
C. 13.6 eV
D. 24.5 eV

Answer

A

Explanation

(a) For hydrogen atom Z=1
`:.` Ionisation energy, `E_(H)=(2pi^(2)me^(4))/(n^(2)h^(2)) " " ...(i)`
For `He^(+)` ion, `(He^(+)=1s^(1))`
so, `(He^(+)=H)` ionisation energy ,
`E_(He^(+))=(2pi^(2)me^(4)Z^(2))/(n^(2)h^(2)) " " ...(ii)`
Eq (i)/Eq (ii), we get
`E_(He^(+))=E_(H)xxZ^(2)=136xx4`
=54.4 eV