Question

Out of the following which one is not a possible energy for a photon to be emitted by a hydrogen atom.

(1) 1.9 eV

(2) 11.1 eV 

(3) 13.6 eV

(4) 0.65 eV

Answer 1

(2) 11.1 eV 

According to Bohr’s theory the energy of a photon emitted when it makes a transition from a quantum state n₂ to n₁ is given by

Also the value of E corresponding to quantum number n is given by E_n = \(-\frac{13.6}{n^2}eV\)

From above we get 

E₁ = -13.6 eV 

E₂ = -3.4 eV 

E₃ = 0.85 eV 

E₄ = 0.58 eV

It is clear that 11.1 eV is not obtainable for the difference of any one of the above given values.