The Earth is assumed to be a sphere of radius $R$. A platform is arranged at a height $R$ from the surface of the Earth. The escape velocity of a body from this platform is $fv$, where $v$ is its escape velocity from the surface of the Earth. the value of $f$ is

  • A

    $\sqrt 2 $

  • B

    $\frac{1}{{\sqrt 2 }}$

  • C

    $\frac{1}{3}$

  • D

    $\frac{1}{2}$

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