PHYSICS, help please!?

Question

The magnetic field perpendicular to a single 10.1 cm diameter circular loop of copper wire decreases uniformly from 0.780 T to zero. If the wire is 2.05 mm in diameter, how much charge moves past a point in the coil during this operation?

Answer 1

I think you are missing information - either the loop moves through this field at some speed, or the field decreases over some time t. Induced voltage, or EMF, is proportional to the rate of change of magnetic field over time, so you need this field to vary somehow with time.