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 –
a. 2
b. 3
c. 4
d. 5