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JEE Main & Advanced Physics Photo Electric Effect, X- Rays & Matter Waves Question Bank Self Evaluation Test - Dual Nature of Radiation and Matter

  • question_answer
    At t=0, light of intensity \[{{10}^{12}}\]\[{{10}^{12}}photons/s-{{m}^{2}}\]of energy 6eV per photon start falling on a plate with work function 2.5eV. If area of the plate is \[2\times {{10}^{-4}}{{m}^{2}}\]and for every \[{{10}^{5}}\]photos one photoelectron is emitted, charge on the plate at \[t=25s\] is

    A) \[8\times {{10}^{-15}}C\]

    B) \[4\times {{10}^{-14}}C\]

    C) \[12\times {{10}^{-14}}C\]

    D) \[16\times {{10}^{-14}}C\]

    Correct Answer: A

    Solution :

    [a] Number of emitted electrons \[=\frac{{{10}^{12}}\times 2\times {{10}^{-4}}\times 25}{{{10}^{5}}}=5\times {{10}^{4}}\text{ electrons}\] \[\text{q=+ne=}8\times {{10}^{-15}}C\]         


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