The binding energy of the electron in the ground state of `He` atom is equal to `E_(0)=24.6 eV`. Find the energy required to remove both the electrons from the atom.

Options

A. 49.2eV
B. 54.4eV
C. 79eV
D. 108.8eV

Answer

C

Explanation

The energy needed to remove one electron form the ground state of He `=24.6eV`.
As the `He^(+)` is now hydrogen -like, ionisation energy
`=|-13.6|(2^2)/(1^2)eVrArrE=54.4eV`
`therefore` To remove both the electrons needed `=(54.4+24.6)eV=79eV`