Hydrogen Spectrum

The ratio of wavelengths of the last line of the Balmer series and the last line of the Lyman series is_____.

Given the value of Rydberg constant is ${10}^7\mathrm{ }{\mathrm{m}}^{-1}$, the wave number of the last line of the Balmer series in hydrogen spectrum will be:

In the spectrum of hydrogen, the ratio of the longest wavelength in the Lyman series to the longest wavelength in the Balmer series is: