Question

state the basic postulates of Bohr's theory of atomic spectra.
hence obtain an expression for the radius of orbit and the energy
at orbital election in a hydrogen atom, write its limitation?
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Answer 1

Answer:

(a) Basic postulates of Bohr's theory are (1) The electron revolves round a nucleus is an atom in various orbits known as stationary orbits. The electrons can not emit radiation when moving in their own stationary levels. (2) The electron can revolve round the nucleus only in allowed orbits whose angular momentum is the integral multiple of h/2π i.e., mυnrn = nh/2π ......... (1) where n = 1, 2, 3..... (3) If an electron jumps from higher energy (E2) orbit to the lower energy (E1) orbit, the difference of energy is radiated in the form of radiation. i.e., E = hν = E2 – E1 ⇒ ν = (E2 E1)/h ...... (2) (b) Energy of emitted radiation : In hydrogen atom, a single electron of charge vector e, revolves around the nucleus of charge e in a circular orbit of radius rn. (1) K.E. of electron : For the electron to be in circular orbit, centripetal force = The electrostatic force of attraction between the electron and nucleus. From Coulomb's law, Read more on Sarthaks.com - https://www.sarthaks.com/534793/state-basic-postulates-bohrs-theory-atomic-spectra-hence-obtain-expression-radius-orbit