Given the value of Rydberg constant is ``10^7m^{-1}``, the
wave number of the last line of the Balmer series
in hydrogen spectrum will be :-
(1) 0.025 × ``10^4m^{-1}``
(2) 0.5 × ``10^7m^{-1}``
(3) 0.25 × ``10^7m^{-1}``
(4) 2.5 × ``10^7m^{-1}``