NEET Sample Paper NEET Sample Test Paper-21

  • question_answer The wavelength of the characteristic .Y-ray \[{{K}_{\alpha }}\]line emitted by a hydrogen-like element is 0.32A. The wavelength of K line emitted by the same element will be:

    A) \[0.24\,\overset{\text{o}}{\mathop{\text{A}}}\,\]                 

    B) \[0.27\,\overset{\text{o}}{\mathop{\text{A}}}\,\]     

    C)   \[0.32\,\overset{\text{o}}{\mathop{\text{A}}}\,\]             

    D)   \[0.48\,\overset{\text{o}}{\mathop{\text{A}}}\,\]                 

    Correct Answer: B

    Solution :

    \[\frac{1}{{{\lambda }_{\alpha }}}={{(z-b)}^{2}}R\left[ \frac{1}{{{1}^{2}}}-\frac{1}{{{1}^{2}}} \right]\] \[\frac{1}{{{\lambda }_{\beta }}}={{(z-b)}^{2}}R\left[ \frac{1}{{{1}^{2}}}-\frac{1}{{{3}^{2}}} \right]\] \[\therefore \]\[\frac{{{\lambda }_{\beta }}}{{{\lambda }_{\alpha }}}=\frac{1-\frac{1}{4}}{1-\frac{1}{9}}=\frac{27}{32}\]\[\therefore \]\[{{\lambda }_{B}}=\frac{27}{32}{{\lambda }_{\alpha }}=\frac{27}{32}\times 0.32\,\overset{\text{o}}{\mathop{\text{A}}}\,\] \[=0.27\,\overset{\text{o}}{\mathop{\text{A}}}\,.\] Hence, the correction option is (b).

adversite


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