What is the use of a line spectra?

What is the use of atomic spectra ?

What is the use of magnetic field lines?

Did Bohr's model account for the splitting of line spectra of a hydrogen atom into finer lines ?

It is a successful model as far as line spectra of hydrogen atom. But it is failed to account for splitting of line spectra. Which model it is ?

What are the postulates of Bohr's model of hydrogen atom ? Discuss the importance of this model to explain various series of line spectra in hydrogen atom.

Which of the following atomic model did not explained the fine line spectra of atoms of more than one electron ?

What does a line spectrum tell us about the structure of an atom?