Question

In a transition to a state of excitation energy 10.19ev, a hydrogen atom emits a 4890Aº photon. The Binding energy of the initial state is -

• A. 1.51 ev
• B. 3.4 ev
• C. 0.54 ev
• D. 0.87 ev

Answer 1

Answer: (D)

0.87 ev

Answer 2

Energy of emitted photon is

E = $\frac{hc}{\lambda}$ = 2.54 ev

The excitation energy is the energy to excite the atom to a level above the ground state. Therefore the energy level is

E = – 13.6 + 10.19 = – 3.41 eV

Photon arises from transition between energy state such that

E_i – E_f = hn = 2.54 eV

E_i = 2.54 + E_f

E_i = 2.54 + (5) = 2.54 – 3.41eV = – 0.87eV