$A$ long rectangular conducting loop of width '$l$',mass '$m$',and resistance '$R$' is placed partly in a perpendicular magnetic field '$B$'. With what velocity should it be pushed downwards so that it may continue to fall without any acceleration? ($g = $ acceleration due to gravity)

  • A
    $\frac{B^2 l^2}{mgR}$
  • B
    $\frac{mgR}{B^2 l^2}$
  • C
    $\frac{B^2 l}{mgR^2}$
  • D
    $\frac{mgR^2}{Bl}$

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