(a). Predict the polarity of capacitor `C` as shown in Fig. 3.26 when poles `S` and `N` of two identical magnets approach the coil from opposote sides with equal velocity. The plane of the loop containing the capacitor is perpendicualr to the plane of the paper.

(b). A magnetic field perpendicular to the plane of a rectangular frame of wire is concentrated about `O`. If the field decreases, will there be any emf induced in loop `1`? What about loop `2`? Explain why.

Explanation

(a) Flux increases towards right, so induced current should be as shown from `2 to 1`. So plate `1` will get positively charged and `2` plate will be negatively charged . ltbr.
(b) In loop `1`, field is inside and is decreasing, so flux is changing within loop `1`, hence emf will be induced. Now, flux through loop `2` will be in upward direction as magnetic field lines are in closed loop. Hence emf will also be induced in loop `2`.