JEE Main & Advanced JEE Main Online Paper (Held On 23 April 2013)

  • question_answer
                    Which of the following statement is Not correct?     [JEE Main Online Paper ( Held On 23  April 2013 )

    A)                   Ground  wave signals are more stable than the sky wave signals.

    B)                                          The critical frequency of an ionospheric layer is the highest frequency that will be reflected back by the layer when it is vertically incident.

    C)                                          Electromagnetic waves of frequencies higher than about 30 MHz cannot penetrate the ionosphere.

    D)                                          Sky wave signals in the broadcast frequency range are stronger at night than in the day time.

    Correct Answer: C

    Solution :

                      Above critical frequency \[({{f}_{c}}),\]an electromagnetic wave penetrates the iono           sphere and is not reflected by it.


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