Toroid

Q.

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 in Fig. 25.21.

The magnitude of the induced electric field at point P at a distance r from the centre of the circular region

1. is zero

2. decreases as $\frac{1}{r}$

3. increases as r

4. decreases as $\frac{1}{r^2}$.