NEET Sample Paper NEET Sample Test Paper-60

  • question_answer
    Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to first excited state. The ratio of the wavelength \[{{\lambda }_{1}}:{{\lambda }_{2}}\] emitted in two cases is:

    A) 7:5       

    B)   27:20  

    C) 27:5                 

    D) 20:7

    Correct Answer: D

    Solution :

    [d] Third excited state n = 4, second excited state n= 3 \[n=4\text{ }\,\,to\,\text{ }n=3\] \[\frac{1}{{{\lambda }_{1}}}=R\left[ \frac{1}{{{(3)}^{2}}}-\frac{1}{{{(4)}^{2}}} \right]\] \[\frac{1}{{{\lambda }_{1}}}=\frac{7R}{144}\] N=3 to n=2 \[\frac{1}{{{\lambda }_{2}}}=R\left[ \frac{1}{{{(2)}^{2}}}-\frac{1}{{{(3)}^{2}}} \right]\] \[\frac{1}{{{\lambda }_{2}}}=\frac{5R}{36}\] \[\frac{{{\lambda }_{1}}}{{{\lambda }_{2}}}=\frac{20}{7}\]


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