The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between

Number of spectral lines obtained due to transition of electron from nth orbit to ground state isN=nn−12 and for maximum wavelength the difference between the orbits of the series should be minimum.Number of spectral lines N=nn−12⇒nn−12=6or          n2−n−12=0or         n−4n+3=0or         n=4Now as the difference in energy between 4 th orbit and 3 rd orbit is minimum , therefore electron jumps from the 4 th orbit to the 3 rd orbit .