NEET AIPMT SOLVED PAPER SCREENING 2011

  • question_answer
    The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for a hydrogen like ion. The atomic number Z of hydrogen like ion is

    A)  4                                            

    B)  1                

    C)  2                                            

    D)  3                

    Correct Answer: C

    Solution :

    Lyman series for H-ion \[\frac{hc}{\lambda }=Rhc\left( \frac{1}{{{1}^{2}}}-\frac{1}{{{2}^{2}}} \right)\] and for H-like ion                          \[\frac{hc}{\lambda }={{Z}^{2}}Rhc\left( \frac{1}{{{2}^{2}}}-\frac{1}{{{4}^{2}}} \right)\] \[\therefore \]  \[\left( \frac{1}{{{1}^{2}}}-\frac{1}{{{2}^{2}}} \right)={{Z}^{2}}\left( \frac{1}{4}-\frac{1}{16} \right)\]                 \[\left( 1-\frac{1}{4} \right)={{Z}^{2}}\left( \frac{1}{4}-\frac{1}{16} \right)\]                 \[Z=2\]


You need to login to perform this action.
You will be redirected in 3 sec spinner