NEET Sample Paper NEET Sample Test Paper-78

  • question_answer
    The angular speed \[\left( \omega  \right)\] of an electron revolving in nth Bohr orbit and corresponding principal quantum number (n) are related as

    A)  \[\omega \propto \frac{1}{{{n}^{3}}}\]                        

    B)  \[\omega \propto \frac{1}{{{n}^{2}}}\]

    C)  \[\omega \propto {{n}^{2}}\]               

    D)  \[\omega \propto {{n}^{3}}\]

    Correct Answer: A

    Solution :

    Velocity, \[v\propto \frac{1}{n}\] \[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,v=\frac{k}{n}\] Also,          \[\operatorname{v} =r\omega \] So,       \[r\omega =\frac{k}{n}\,\,\,\,\,\,\,\,\Rightarrow \,\,\,\,\,\,\omega =\frac{k}{nr}\] Now, radius,   \[\operatorname{r}\propto {{n}^{2}}\] \[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,r=k'{{n}^{2}}\] So,  \[\omega =\frac{k}{n(k'{{n}^{2}})}=\frac{k}{k({{n}^{3}})}\] \[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\omega \propto \frac{1}{{{n}^{3}}}\]


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