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

  • question_answer
    In a Millikan's oil drop experiment the charge on an oil drop is calculated to be \[6.35\times {{10}^{-19}}C\]. The number of excess electrons on the drop is                                                            [MNR 1998]

    A)            3.9 

    B)            4

    C)            4.2 

    D)            6

    Correct Answer: B

    Solution :

               \[n=\frac{Q}{e}=\frac{6.35\times {{10}^{-19}}}{1.6\times {{10}^{-19}}}\approx 4\]


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