Manipal Medical Manipal Medical Solved Paper-2000

  • question_answer
    Taking Rydbergs constant\[{{R}_{H}}=1.097\]\[\times {{10}^{7}}m\] first and second wavelength of Balmer series m hydrogen spectrm, is:

    A)  \[2000\overset{o}{\mathop{\text{A}}}\,,3000\overset{o}{\mathop{\text{A}}}\,\]   

    B)  \[1575\overset{o}{\mathop{\text{A}}}\,,2960\overset{o}{\mathop{\text{A}}}\,\]

    C)  \[6529\overset{o}{\mathop{\text{A}}}\,,4280\overset{o}{\mathop{\text{A}}}\,\]  

    D)  \[6552\overset{o}{\mathop{\text{A}}}\,,4863\overset{o}{\mathop{\text{A}}}\,\]

    Correct Answer: D

    Solution :

     The wavelength of the lines in Balmer series is represented by, \[\frac{1}{\lambda }={{R}_{H}}\left[ \frac{1}{{{2}^{2}}}-\frac{1}{n_{2}^{2}} \right]\] For first wavelength \[\frac{1}{{{\lambda }_{1}}}=1.097\times {{10}^{7}}\left[ \frac{1}{{{2}^{2}}}-\frac{1}{{{3}^{2}}} \right]\] \[=1.524\times {{10}^{6}}m\] Or \[{{\lambda }_{1}}=\frac{1}{1.524\times {{10}^{6}}}=6.562\times {{10}^{-7}}\] Or \[{{\lambda }_{1}}=6562\overset{o}{\mathop{\text{A}}}\,\] For second wavelength \[\frac{1}{{{\lambda }_{1}}}=1.097\times {{10}^{-7}}\left[ \frac{1}{{{2}^{2}}}-\frac{1}{{{4}^{2}}} \right]\] \[=2.056\times {{10}^{6}}\] Or \[{{\lambda }_{2}}=\frac{1}{2.056\times {{10}^{6}}}\] Or \[{{\lambda }_{2}}=4.863-7\times 10\times {{10}^{-10}}\] Or \[{{\lambda }_{2}}=4863\overset{o}{\mathop{\text{A}}}\,\]


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