The ratio of longest wavelength and the shortest wavelength observed in the five spectral series of emission spectrum of hydrogen is

Shortest wavelength comes from n1=∞ to n2=1 and longest wavelength comes from n1=6 to n2=5 in the given case. Hence 1λmin=R 112-1∞2=R 1λmax=R 152-162=R 36-2525×36=11900R∴λmaxλmin=90011