This question has Statement–1 and Statement–2. Of the four choices given after the Statements, choose the one that best describes the two Statements.
Statement–1: Short wave transmission is achieved due to the total internal reflection of the e–m wave from an appropriate height in the ionosphere.
Statement–2: Refractive index of a plasma is independent of the frequency of e–m waves.

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Statement–1 is true, Statement–2 is true but Statement–2 is not the correct explanation of Statement–1

Statement–1 is true, Statement–2 is false

Statement–1 is true, Statement–2 is true but Statement–2 is correct explanation of Statement–1

Statement–1 is false, Statement–2 is true

answer is A.

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Detailed Solution

Statement–1: True
As in sky wave propagation we use frequency upto 30MHz. (short waves) and long distance communication is possible due to reflection by ionospheric layers.
Statement–2: Not correct
In ionosphere $\to$ plasma. (free ions) The frequency which are above 30 MHz can penetrate the atmosphere $\to$ No total internal reflection occurs because with frequency Refractive Index of ionosphere changes.

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