NEET Sample Paper NEET Sample Test Paper-44

  • question_answer
    An electron of a stationary hy4rogen atom passes from the 5th energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be:

    A) \[\frac{24Rh}{25m}\]                            

    B) \[\frac{25hR}{24m}\]     

    C) \[\frac{25m}{24hR}\]                            

    D) \[\frac{24m}{25hR}\]

    Correct Answer: A

    Solution :

    \[\frac{1}{\lambda }=R\left[ \frac{1}{{{n}^{2}}_{f}}-\frac{1}{{{n}^{2}}_{1}} \right]\] \[{{n}_{f}}=1,\,\,\,{{n}_{1}}=5\] \[\frac{1}{\lambda }=R\left[ 1-\frac{1}{{{\left( 5 \right)}^{2}}} \right]=\frac{24}{25}R\] Apply momentum conservation Momentum of photon = momentum of atom \[\frac{\operatorname{h}}{\lambda }=mv\] \[\operatorname{v}=\frac{h}{m\lambda }=\frac{h}{m}\times \frac{24}{25}R\] \[\operatorname{v}=\frac{24hR}{25m}\]


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