Assume that their is no repulsive force be -tween the electrons in an atom but the force between positive and negative charges is given by Coulomb's law as usual . Under such circumtences, calculate the ground state energy of a He-atom.

Explanation

When effect of electrons on outer electrons of atom is not considered then we can use Bohr.s formula with atomic number of atom. According to Bohr.s formula, energy of `n^(th)` energy level of atom with atomic number Z is given by
`E_n=(-(Z^2)me^4)/(8epsilon_0^2n^2h^2)`
For He atom,
Z=2
`therefore E_n=(-(2^2)me^4)/(8epsilon_0^2 n^2h^2)`=4E
Where E is the ground state energy of hydrogen atom=-13.6 eV
Thus, ground state energy of He-atom = 4 x (-13.6) eV
=-54.4 eV