JEE Main & Advanced Physics Electrostatics & Capacitance JEE PYQ-Electrostatics and Capacitance

  • question_answer
    The flat base of a hemisphere of radius a with no charge inside it lies in a horizontal plane. A uniform electric field E is applied at an angle\[\frac{\pi }{4}\]with the vertical direction. The electric flux through the curved surface of the hemisphere is [JEE ONLINE 19-05-2012]

    A) \[\pi {{a}^{2}}E\]

    B) \[\frac{\pi {{a}^{2}}E}{\sqrt{2}}\]

    C)             \[\frac{\pi {{a}^{2}}E}{2\sqrt{2}}\]

    D) \[\frac{\left( \pi +2 \right)\pi {{a}^{2}}E}{{{\left( 2\sqrt{2} \right)}^{2}}}\]

    Correct Answer: B

    Solution :

    [b] We know that,\[\phi =\oint{E.dS=E}\oint{dS}\cos {{45}^{o}}\]
    In case of hemisphere\[{{\phi }_{curved}}={{\phi }_{circular}}\]
    Therefore, \[{{\phi }_{curved}}=E\pi {{a}^{2}}\frac{1}{\sqrt{2}}=\frac{E\pi {{a}^{2}}}{\sqrt{2}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner