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JEE Main & Advanced Sample Paper JEE Main Sample Paper-22

  • question_answer
    Frequencies higher than 10 MHz are foam not to be reflected by the ionosphere on a particular day at a place, than the maximum electron density of ionosphere will be:

    A)  \[1.25\times {{10}^{12}}{{m}^{-3}}\]           

    B)  \[1.25\times {{10}^{6}}{{m}^{-3}}\]

    C)  \[2\times {{10}^{12}}{{m}^{-3}}\]               

    D)  \[2\times {{10}^{6}}{{m}^{-3}}\]     

    Correct Answer: A

    Solution :

    \[{{f}_{critical}}=9\times {{({{N}_{\max }})}^{1/2}}\] \[{{N}_{\max }}\,=1.25\,\times {{10}^{12}}\,{{m}^{-3}}\]


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