The figure shows three situations when an electron with velocity $\vec v$ travels through a nuniform magnetic field $\vec B$ . In each case, what is the direction of magnetic force on the electron?

822-296

  • A

    positive $z-$ axis, negative $x-$ axis, positive $y-$ axis

  • B

    negative $z-$ axis, negative $x-$ axis and zero

  • C

    positive $z-$ axis, positive $y-$ axis and zero

  • D

    negative $z-$ axis, positive $x-$ axis and zero

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