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12th Class Physics Electric Charges and Fields Question Bank MCQ - Electric Charges and Fields

  • question_answer
    Electric field at a point of distance r from a uniformly charged wire of infinite length having Linear charge density                                                                                 \[\lambda\] is directly proportional to:

    A)                                                                              \[{{r}^{-1}}\]                                    

    B) r

    C)                                                                              \[{{r}^{2}}\]                                    

    D)                                                                              \[{{r}^{-2}}\]

    Correct Answer: A

    Solution :

                                                                                   \[{{r}^{-1}}\] We know that, electric field at distance r from an infinitely long line charge is given by              \[E=\frac{\lambda }{2\pi {{\varepsilon }_{0}}r}\Rightarrow \lambda =2\pi {{\varepsilon }_{0}}\,.\,rE\]                                                                       \[E\propto {{r}^{-1}}\]


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