Ratio of shortest wavelength of Balmer series in a hydrogen atom to that of Lymann series in a He+ ion is

for any series shortest wavelength can be given by  1λ=RZ21n2-1∞  where R is the Rydberg's constant and Z is the atomic no.For Balmer series in hydrogen atom 1λ1=R122−1∝=R4For Lymann series of He+ is 1λ2=4R112-1∞∴ λ1λ2=4/R1/4R=16