Question

the energy required to excite an electron in hydrogen atom to its first excited state is
A. `8.5eV`
B. `10.2eV`
C. `12.7eV`
D. `13.6eV`

Answer 1

Correct Answer - B
Energy , `E_n=-(13.6)/(n^2)eV`
In ground state energy `E_1=-(13-6)/(1^2)=-13.6eV`
In first excited state energy `E_2=-(13.6)/(2^2)=-3.4eV`
Then the required energy `=E_2-E_1=-3.4-(-13.6)=10.2eV`