The total energy of eletcron in the ground state of hydrogen atom is `-13.6 eV`. The kinetic enegry of an electron in the first excited state is

Options

A. `3.4 eV`
B. `6.8 eV`
C. `13.6 eV`
D. `1.7 eV`

Answer

A

Explanation

Total enegry of electron in the orbit is equal to negative of its kinetic energy.
The energy of hydrogen atom when the electron revolves in `nth` orbit is
`E = (-13.6)/(n^(2))eV`
In ground state `n = 1`
`E = (-13.6)/(1^(2)) =- 13.6 eV`
For `n = 2, E = (-13.6)/(2^(2)) =- 3.4 eV`
So, kinetic energy of electron in the first excited state (i.e., for `n = 2`) is
`K = -E =- (-3.4) = 3.4 eV`