The binding energy of an electron in the ground state of He is equal to 24.6eV. The energy required to remove both the electron is

Options

A. `24.6 eV`
B. `79.0 eV`
C. `54.4 eV`
D. none of these

Answer

b

Explanation

The total energy required too make the electron free from nucleus is the sum of the enrgy required to seprate the electrons from the influences of each other and the energy required to seprate the electrons from the influences of nucleus, i.e.,
Total required energy = BE of electron in He atom + ioniztion energy of He atom
`=(24.6 + 13.6 xx 2^(2))eV`
`=(24.6 +54.4)eV=79 eV` .