How does Bohr’s model of atom explain characteristic spectra of different atoms and ionisation of gases in the discharge tube experiment?
In Bohr's model of atom, the electrons can occupy orbits with discrete energy levels only. Thus, when an electron falls from a higher energy level to a lower one, the difference in energy is radiated in the form of electromagnetic radiation of a fixed wavelength only. Since each atom has its specific energy levels, it can emit radiations of specific wavelength. This explains why different atoms give different or characteristic atomic spectra.
When the electron is so excited due to external energy that it is able to overcome force between it and the positively charged nucleus, it comes out of the atom. This explains the formation of cathode rays in the discharge tube. This is also known as ionization of gases.
