Physics-
General
Easy
Question
A uniform but time-varying magnetic field B(t) exists in a circular region of radius a and is directed into the plane of the paper, as shown. The magnitude of the induced electric field at point P at a distance r from the centre of the circular region
- Is zero
- Decreases as
- Increases as r
- Decreases as
The correct answer is: Decreases as
Construct a concentric circle of radius r. The induced electric field (E) at any point on the circle is equal to that at P. For this circle
or 
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