RAJASTHAN ­ PET Rajasthan PET Solved Paper-2010

  • question_answer
    Ultraviolet radiation of 6.2 eV falls on an aluminium surface (work function 4.2 eV). The kinetic energy in joule of the fastest electron emitted is approximately

    A)  \[3.2\times {{10}^{-21}}\]        

    B)  \[3.2\times {{10}^{-19}}\]

    C)  \[3.2\times {{10}^{-17}}\]        

    D)  \[3.2\times {{10}^{-15}}\]

    Correct Answer: B

    Solution :

     \[{{K}_{\max }}(eV)=E(eV)-{{W}_{0}}(eV)\] \[=6.2-4.2=2eV\] \[\therefore \] \[{{K}_{\max }}(J)=2\times 1.6\times {{10}^{19}}J\] \[=3.2\times {{10}^{-19}}J\]


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