At a distance $l$ from a uniformly charged long wire, a charged particle is thrown radially outward with a velocity $u$ in the direction perpendicular to the wire. When the particle reaches a distance $2 l$ from the wire, its speed is found to be $\sqrt{2} u$. The magnitude of the velocity, when it is a distance $4 l$ away from the wire is (ignore gravity)

  • [KVPY 2011]
  • A

    $\sqrt{3} u$

  • B

    $2 u$

  • C

    $2 \sqrt{2} u$

  • D

    $4 u$

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