Question

Three photons coming from excited atomic-hydrogen sample are picked up. Their energies are 12.1 eV, 10.2 eV and 1.9 eV. These photons must come from
(a) a single atom
(b) two atoms
(c) three atoms
(d) either two atoms or three atoms

Answer 1

Three photons with energy 12.1,10.2 and 1.9 ev coming from excited atomic hydrogen are coming from a single hydrogem atom.

1)Photons coming from a different atom of hydrogen would seem to have some same energies .

2)However every photon has different energy then it must be coming from a single hydrogen atom.

Answer 2

Three photons coming from the excited atomic-hydrogen samples are picked up. Their energies are 12.1 eV, 10.2 eV and 1.9 eV. These photons must come from (d) either two atoms or three atoms.

Explanation:

• We know that according to Bohr’s model, The energy ∆E released by the electron when it moves from one energy level n1 to other energy level n2 is given by,

       $\Delta E=13.6\left(\frac{1}{n_{1}^{2}}-\frac{1}{n_{2}^{2}}\right)$

• By considering three transactions such as n3 to n2 and n2 to n1 and n3 to directly n1, we can get the following values of energy released such as 12.1 eV, 10.2 eV and 1.9 eV.
• Hence we can conclude that three transaction are involved and it is not possible for a single atom to get involved in all three transactions are Hence option a) can’t be right and it is ignored.
• And and it has three transactions, Either two or three atoms can get involved in this and hence option d) is concluded as right answer.