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.
The quantum number n of the state finally populated in `He^(+)` ions is :

Options

A. `(1)/(4)`
B. `(1)/(2)`
C. `1`
D. `2`

Answer

A

Explanation

`K.E= - T.E`
`(K_(H))/(K_(He))=(TE_(H))/(TE_(He))`
For same `'n'" " (TE_(H))/(TE_(He))=((Z_(H))^(2))/((Z_(He))^(2)) = (1)/(4)`