NEET Sample Paper NEET Sample Test Paper-86

  • question_answer
    What is the ratio of the shortest wavelength of the Balmer series to the shortest wavelength of the Lyman series?

    A) 4 : 1                 

    B)        4 : 3

    C) 4 : 9                 

    D)        5 : 9

    Correct Answer: A

    Solution :

    [a] For Lyman series \[\frac{1}{\lambda }=R\left[ \frac{1}{{{1}^{2}}}-\frac{1}{{{n}^{2}}} \right]\] For shortest wavelength, \[n=\infty ,\] \[\therefore \]      \[\theta =\frac{64}{2}=32{}^\circ C.\]\[\Rightarrow \]\[{{\lambda }_{1}}=\frac{1}{R}\] For Banner series \[\frac{1}{{{\lambda }_{2}}}=R\left[ \frac{1}{{{2}^{2}}}-\frac{1}{{{n}^{2}}} \right]\] For shortest wavelength, \[n=\infty ,\] \[\therefore \]      \[\frac{1}{{{\lambda }_{2}}}=\frac{R}{4}\]\[\Rightarrow \]\[{{\lambda }_{2}}=\frac{4}{R}\] The ratio \[\frac{{{\lambda }_{2}}}{{{\lambda }_{1}}}=\frac{4}{1}.\]


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