JEE Main & Advanced Physics Photo Electric Effect, X- Rays & Matter Waves Question Bank Photon and Photoelectric Effect

  • question_answer
    The cathode of a photoelectric cell is changed such that the work function changes from W1 to W2 (W2>W1). If the current before and after change are I1 and I2, all other conditions remaining unchanged, then (assuming hn > W2) [CBSE PMT 1992]

    A)            \[{{I}_{1}}={{I}_{2}}\]       

    B)            \[{{I}_{1}}<{{I}_{2}}\]

    C)            \[{{I}_{1}}>{{I}_{2}}\]       

    D)            \[{{I}_{1}}<{{I}_{2}}<2{{I}_{1}}\]

    Correct Answer: A

    Solution :

               The work function has no effect on current so long as \[h\nu >{{W}_{0}}\]. The photoelectric current is proportional to the intensity of light. Since there is no change in the intensity of light, therefore \[{{I}_{1}}={{I}_{2}}\].


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