EAMCET Medical EAMCET Medical Solved Paper-2008

  • question_answer
    The wavelength (in\[\,\overset{\text{o}}{\mathop{\text{A}}}\,\]) of an emission line obtained for \[\text{L}{{\text{i}}^{2+}}\]during an electronic transition  from  \[{{n}_{2}}=2\]  to  \[{{n}_{1}}=1\]  is (R = Rydberg constant)

    A)  \[\frac{3R}{4}\]                                               

    B)  \[\frac{27R}{4}\]

    C)  \[\frac{4}{3R}\]                                               

    D)  \[\frac{4}{27R}\]

    Correct Answer: D

    Solution :

    \[\frac{1}{\lambda }=R{{Z}^{2}}\left( \frac{1}{n_{1}^{2}}-\frac{1}{n_{2}^{2}} \right)\] where,                 \[Z=3\] (\[\because \] for \[\text{L}{{\text{i}}^{\text{2+}}}\]atomic no. =3) \[{{n}_{2}}=2,\,\,{{n}_{1}}=1\] \[\frac{1}{\lambda }=R{{(3)}^{2}}\left( \frac{1}{{{(1)}^{2}}}-\frac{1}{{{(2)}^{2}}} \right)\] \[\lambda =\frac{R\times 9\times 3}{4}\] \[\lambda =\frac{4}{27R}\]


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