A transition for H-atom from II to I orbit has same wavelength as from `n^(th)` orbit to `2^(nd)` orbit for `He^+` ion. The value of ‘n’ is _________ .

Answer

2

Explanation

`1/lambda = R [1/1 - 1/4] = 4 R [1/4 - 1/(n_2^2)] therefore n^2 = 4`