Haryana PMT Haryana PMT Solved Paper-2009

  • question_answer
    43.     For hydrogen atom electron in \[{{\text{n}}^{\text{th}}}\] Bohr orbit, the ratio of radius of orbit to its de-Broglie                 wavelength is

    A)                 \[\frac{n}{2\pi }\]                                            

    B) \[\frac{{{n}^{2}}}{2\pi }\]

    C)                 \[\frac{1}{2\pi n}\]                                         

    D) \[\frac{1}{2\pi {{n}^{2}}}\]

    Correct Answer: A

    Solution :

                    For nth Bohr orbit,                           \[r=\frac{{{\varepsilon }_{0}}{{n}^{2}}{{h}^{2}}}{\pi mZ{{e}^{2}}}\] de-Broglie wavelength \[\lambda =\frac{h}{mv}\] Ratio of both r and \[\lambda \], we have                 \[\frac{r}{\lambda }=\frac{{{\varepsilon }_{0}}{{n}^{2}}{{h}^{2}}}{\pi mZ{{e}^{2}}}\times \frac{mv}{h}\]                 \[=\frac{{{\varepsilon }_{0}}{{n}^{2}}hv}{\pi Z{{e}^{2}}}\] But \[v=\frac{Z{{e}^{2}}}{2h{{\varepsilon }_{0}}n}\] for nth orbit Hence,    \[\frac{r}{\lambda }=\frac{n}{2\pi }\]


You need to login to perform this action.
You will be redirected in 3 sec spinner