Question 87: Atoms & Nuclei

Question

In a mixture of H - He$$^+$$ gas (He$$^+$$ is singly ionized He atom), H atoms and He$$^+$$ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He$$^+$$ ions (by collisions). Assume that the Bohr model of atom is exactly valid.

Accepted Answer

For H atom,
$${E_1} =  - {{13.6} \over {{1^2}}} =  - 13.6\,eV$$
$${E_2} =  - {{13.6} \over {{2^2}}} =  - 3.4\,eV$$
Energy released by H atom = E$$_2$$ $$-$$ E$$_1$$
$$ =  - 3.4 - ( - 13.6) = 10.2\,eV$$
This energy will be absorbed by He atom. Thus, for He atom
$$10.2 =  - 13.6 	imes {2^2}\left( {{1 \over {{2^2}}} - {1 \over {{n^2}}}} ight)$$
$$0.1875 = {1 \over 4} - {1 \over {{n^2}}}$$
$${n^2} = 16$$
$$n = 4$$

Answer

2

Answer

3

Answer

4

Answer

5

Atoms & Nuclei

In a mixture of H - He$^+ gas (He^+ is singly ionized He atom), H atoms and He^+ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He^+$ ions (by collisions). Assume that the Bohr model of atom is exactly valid.

Choose the correct answer: