# Electric field induced in a ring

1. Homework Statement
A metal ring 4.6 cm. in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. These magnets produce an initial uniform field of 1.12 T between them but are gradually pulled apart, causing this field to remain uniform but decrease steadily at 0.260 T/s.

a.) What is the magnitude of the electric field induced in the ring?

2. Homework Equations

Flux = BA
Induced EMF = -dFlux/dt

The change in magnetic field, it seems, should be affecting the magnetic flux through the ring and thus inducing a counter-clockwise current. I thought that this change in flux could be expressed by (.260 T/s)*(2(pi)(4.6cm/2)^2) or the change in magnetic field times the area, but this is wrong. I don't really know where to begin, any help would be appreciated.

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1. Homework Statement
A metal ring 4.6 cm. in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. These magnets produce an initial uniform field of 1.12 T between them but are gradually pulled apart, causing this field to remain uniform but decrease steadily at 0.260 T/s.

a.) What is the magnitude of the electric field induced in the ring?

2. Homework Equations

Flux = BA
Induced EMF = -dFlux/dt

The change in magnetic field, it seems, should be affecting the magnetic flux through the ring and thus inducing a counter-clockwise current. I thought that this change in flux could be expressed by (.260 T/s)*(2(pi)(4.6cm/2)^2) or the change in magnetic field times the area, but this is wrong. I don't really know where to begin, any help would be appreciated.
I think you got the area wrong. 4.6 cm is the diameter and not the radius. You also need the area in m^2