Physics

Problem

The radius of a circular coil of 200 turns is shrinking at a constant rate of

1.0\,\text{mm}\,\text{s}^{-1}

while it is placed in a uniform magnetic field of

0.50\,\text{T}

directed perpendicular to the plane of the coil. When the radius is

10\,\text{cm}

, the magnitude of the induced emf in the coil is a)

31\,\text{mV}

63\,\text{mV}

6.3\,\text{mV}

0.63\,\text{V}