RAJASTHAN PMT Rajasthan - PMT Solved Paper-2007

  • question_answer
    A light of wavelength \[5000\overset{\text{o}}{\mathop{\text{A}}}\,\] falls on a sensitive plate with photoelectric work function 1.90 eV. Kinetic energy of the emitted photoelectrons will be (Given, \[(\text{Give}\,\text{n,}\,\text{h=6}\text{.62}\times \text{1}{{\text{0}}^{-34}}\text{J-s})\]

    A)  0.1 eV                                 

    B)  2 eV

    C)  0 58 eV               

    D)         1.581 eV

    Correct Answer: C

    Solution :

    From photoelectric equation                 \[E=hv=\frac{hc}{\lambda }\] \[\therefore \]  \[E=\frac{6.6\times {{10}^{-34}}\times 3\times {{10}^{8}}}{5000\times {{10}^{-10}}}\]                    \[=3.96\times {{10}^{-19}}J\] Also,      \[1eV=1.6\times {{10}^{-19}}J\] \[\therefore \]  \[E=\frac{3.96\times {{10}^{-19}}}{1.6\times {{10}^{-19}}}=2.48\,\,eV\] Hence,\[{{E}_{k}}=2.48-1.90=0.58\,\,eV\]


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