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

PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences

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}

(b)

63\,\text{mV}

(c)

6.3\,\text{mV}

(d)

0.63\,\text{V}