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Atoms — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsAtoms3 Marks
Question
Explain the assumption related to quantization of angular momentum in Bohr's theory.###Explain quantum condition for orbital motion of electron in hydrogen atom.###Explain Bohr's second postulate of quantisation by de Broglie hypothesis.
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Answer

Bohr's Second Postulate : Electron revolves only those orbits in which the angular momentum $( L =m v r)$ is multiple integer of $\frac{h}{2 \pi}$.
According to Bohr's this postulate, $L =\frac{n h}{2 \pi}$
or $\quad m v r=\frac{n h}{2 \pi} \quad$ Where $n$ is an integer whose values are $n=1,2,3, \ldots \ldots$ respectively.
$n$ is principal quantum number and this condition is called Bohr's quantum condition. Motion of electron is limited in possible orbits by this condition.
The stable orbits of different radii of electron can be obtained by given the different values to $n$.

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