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NEET Sample Paper NEET Sample Test Paper-17

  • question_answer
    Light of two different frequencies whose photons have energies 1 and 2.5 eV, respectively, successively illuminate a metal whose work function is 0.5 eV. The ratio of the maximum speeds of the emitted electrons will be:

    A)  1 : 5                           

    B)  1 : 4                           

    C)  1 : 2                  

    D)    1 : 1

    Correct Answer: C

    Solution :

    If E is the energy incident on photon and \[{{W}_{0}}\]the work function, then \[E-{{W}_{0}}=\]available energy \[E-{{W}_{0}}=\frac{1}{2}m{{v}^{2}}\]or \[v=\sqrt{2\left( \frac{E-{{W}_{0}}}{m} \right)}\] \[\because \]  \[\frac{{{v}_{1}}}{{{v}_{2}}}=\sqrt{\frac{1-0.5}{2.5-0.5}}=\sqrt{\frac{0.5}{2}}=\frac{1}{2}\] Hence, the correction option is [c].


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