Here, we need the explain number of line spectrum in hydrogen atom in light of the Bohr's concept of orbit around the nucleus.
As per the Rutherford's atomic structure the one electron which remains in hydrogen atom can generate only one line of its spectrum. However Niels Bohr observe there are many lines in the spectrum of hydrogen.
From this observation the concept of different orbit around a nucleus of an atom generated. Which nicely can explain the number of lines in the hydrogen atom spectrum.
To have many spectral lines of an one electron atom there must be number of orbitals in which the electron can jump. If there are 4 orbitals (say). The one electron can jump from n₁ to n₂, n₂ to n₃ and so on.
Thus, it reveals there are number of orbitals around the nucleus of the hydrogen atom, for which although it has only one electron can give number of lines in its spectrum.
