The atomic hydrogen emits lines spectrum consisting of various series.: Name the series observed first.

The atomic radii of the second and third transition series are almost the same. Why?

Bohr was the first to explain the structure of hydrogen atom and spectrum. Calculate the wavelength of the first line in the Lyman series of the hydrogen spectrum. ( R= 109677 cm^(-1))

Which series of hydrogen spectra lies in the visible region?

The atomic radii of the elements are almost same of which series