A circular conducting loop of resistance has radius at an instant when it lies in a…

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

Problem

A circular conducting loop of resistance

2.0\,\Omega

has radius

0.25\,\text{m}

at an instant when it lies in a spatially uniform magnetic field of magnitude

0.60\,\text{T}

directed perpendicular to the plane of the loop. At that instant the radius is decreasing at a rate of

0.010\,\text{m/s}

, and the magnetic field magnitude is increasing at a rate of

0.020\,\text{T/s}

. What is the magnitude of the current induced in the loop at that instant? (a)

6.7\,\text{mA}

(b)

2.8\,\text{mA}

(c)

2.0\,\text{mA}

(d)

4.7\,\text{mA}