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NEET Sample Paper NEET Sample Test Paper-20

  • question_answer
    The velocity of the most energetic electron emitted from a metallic surface is doubled when the frequency v of incident radiation is doubled. The work function of this metal is

    A) \[\frac{2}{3}hv\]                                

    B) \[\frac{hv}{2}\]                      

    C)  \[\frac{hv}{3}\]                     

    D)        0

    Correct Answer: A

    Solution :

    \[hv-\phi =\frac{1}{2}mv_{\max }^{2}\] Also, \[h(2v)-{{\phi }_{0}}=\frac{1}{2}m{{(2{{v}_{\max }})}^{2}}\] \[\Rightarrow \]\[2hv-{{\phi }_{0}}=4(hv-{{\phi }_{0}})\]\[\therefore \]\[{{\phi }_{0}}=\frac{2}{3}hv\] Hence, the correction option is (a).


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