JEE Main & Advanced Physics Electrostatics & Capacitance Question Bank Self Evaluation Test - Electrostatic Potential and Capacitance

  • question_answer
    The energy required to change a parallel plate condenser of plate separation d and plated area of cross-section A such that the uniform electric field between the plates is E, is

    A) \[{{\in }_{0}}{{E}^{2}}Ad\]               

    B) \[\frac{1}{2}{{\in }_{0}}{{E}^{2}}Ad\]

    C) \[\frac{1}{2}{{\in }_{0}}{{E}^{2}}/Ad\]

    D)        \[{{\varepsilon }_{0}}{{E}^{2}}/Ad\]

    Correct Answer: A

    Solution :

    [a] Energy required to charge the capacitor is \[W=U=QV\] \[\Rightarrow U=C{{V}^{2}}=\frac{{{\varepsilon }_{0}}A}{d}{{y}^{2}}=\frac{{{\varepsilon }_{0}}Ad}{{{d}^{2}}}\] \[{{V}^{2}}={{\varepsilon }_{0}}{{E}^{2}}Ad\text{            }\left[ \because E=\frac{V}{d} \right]\]


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