The energy of an electron in the first Bohr orbit of H-atom is eV. The possible energy value(s) of the excited state(s) for electrons in Bohr orbits of hydrogen is (are)
- A.eV
- B.eV
- C.eV
- D.eV
Show answer and solution
Correct option: A
Solution
The energy of the nth Bohr orbit is En = -13.6/n² eV. For excited states, n = 2, 3, 4, ... giving allowed energies -3.4 eV (n=2), -1.51 eV (n=3), etc. Only -3.4 eV matches this formula (n=2). The values -4.2 eV and -6.8 eV do not correspond to any integer n, and +6.8 eV is positive which is impossible for a bound electron in hydrogen.
[1998]