WB JEE Medical WB JEE Medical Solved Paper-2013

  • question_answer
    Ratio   of   longest   wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is

    A) \[\frac{5}{27}\]

    B)  \[\frac{3}{23}\]

    C)  \[\frac{7}{29}\]

    D)  \[\frac{9}{31}\]

    Correct Answer: A

    Solution :

     Wavelength for Lyman series \[{{\lambda }_{L}}=\frac{1}{R\left( 1-\frac{1}{4} \right)}=\frac{4}{3R}\] and wavelength for Balmer series \[{{\lambda }_{B}}=\frac{1}{R\left( \frac{1}{4}-\frac{1}{9} \right)}=\frac{1}{R\left( \frac{5}{36} \right)}=\frac{36}{5R}\] \[\therefore \] \[\frac{{{\lambda }_{L}}}{{{\lambda }_{B}}}=\frac{4}{3R}\times \frac{5R}{36}=\frac{5}{27}\] \[\Rightarrow \] \[{{\lambda }_{L}}:{{\lambda }_{B}}=5:27\]


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