In Bohr series of lines of hydrogen spectrum the third line

 

Question :- In Bohr series of lines of hydrogen spectrum the third line from the red end corresponds to which one of the following inner orbit jumps of electron for Bohr’s orbit in atom of hydrogen

(A)  3 → 2

(B)  5 → 2

(C)  4 → 1

(D)  2 → 5

Solution :-

Red end means it is a part of the visible region and obviously only Blamer series corresponds to the visible region.

Now

The first line of Blamer series is n = 3 to n =2
The second line of Blamer series is n = 4 to n = 2
The third line of Blamer series is n = 5 to n = 2

Hence correct option is (B).