$A$ metal disc of radius $R$ rotates with an angular velocity $\omega$ about an axis perpendicular to its plane passing through its centre in a magnetic field of induction $B$ acting perpendicular to the plane of the disc. The induced e.m.f. between the rim and axis of the disc is:

  • A
    $B \pi R^2$
  • B
    $\frac{2 B \pi^2 R^2}{\omega}$
  • C
    $B \pi R^2 \omega$
  • D
    $\frac{BR^2 \omega}{2}$

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