JEE Main & Advanced JEE Main Paper Phase-I Held on 07-1-2020 Morning

  • question_answer
    If the magnetic field in a plane electromagnetic wave is given by \[\overline{B}=3\times {{10}^{-8}}\sin (1.6\times {{10}^{3}}x+48\times {{10}^{10}}t)\hat{j}T\], then what will be expression for electric field? [JEE MAIN Held on 07-01-2020 Morning]

    A) \[\vec{E}=\left( 60\sin (1.6\times {{10}^{3}}x+48\times {{10}^{10}}t)\hat{k}V/m \right)\]

    B) \[\vec{E}=\left( 3\times {{10}^{-8}}\sin (1.6\times {{10}^{3}}x+48\times {{10}^{10}}t)\hat{i}V/m \right)\]

    C) \[\vec{E}=\left( 9\sin (1.6\times {{10}^{3}}x+48\times {{10}^{10}}t)\hat{k}V/m \right)\]

    D) \[\vec{E}=\left( 3\times {{10}^{-8}}sin(1.6\times {{10}^{3}}x+48\times {{10}^{10}}t)\hat{j}V/m \right)\]

    Correct Answer: C

    Solution :

    [c] \[\vec{B}=3\times {{10}^{-8}}\sin \left( 1.6\times {{10}^{3}}x+48\times {{10}^{10}}t \right)\hat{j}T\] \[{{E}_{0}}={{B}_{0}}\times C=3\times {{10}^{-8}}\times 3\times {{10}^{8}}=9\,V/m\] \[\therefore \vec{E}=9\sin \left( 1.6\times {{10}^{3}}x+48\times {{10}^{10}}t \right)\hat{k}\,V/m\]


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