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JEE Main & Advanced Physics Electrostatics & Capacitance Question Bank Self Evaluation Test - Electric Chages and Fields

  • question_answer
    The magnitude of the average electric field normally present in the atmosphere just above the surface of the Earth is about 150 N/C, directed inward towards the center of the Earth. This gives the total net surface charge carried by the Earth to be: [Given \[{{\varepsilon }_{0}}=8.85\times {{10}^{-12}}{{C}^{2}}/N-{{m}^{2}},\]\[{{R}_{E}}=\]\[6.37\times {{10}^{6}}m\]] magnitude of the average electric field normally present in the atmosphere just above the surface of the Earth is about 150 N/C, directed inward

    A) +670kC

    B) -670kC

    C) -680kC

    D) +680kC

    Correct Answer: C

    Solution :

    [c] Given, Electric field \[E=150N/C\] Total surface charge carried by earth \[q=?\] According to Gauss's law. \[\phi =\frac{q}{{{\varepsilon }_{0}}}=EA\] or, \[q\,\,={{\in }_{0}}EA\,\,\,=\,\,{{\in }_{0}}E\pi {{r}^{2}}=8.85\times {{10}^{-12}}\times 150\times \]\[{{(6.37\times {{10}^{6}})}^{2}}.\]As electric field directed inward hence \[q=-\,680KC\]


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