This is not a problem from any book or any kind of source. I was just thinking on this. Suppose u have a capacitor attached to a battery. And then u insert the dielectric slab. Then do the electric field between the plates changes???
The Attempt at a Solution
I think it should not.Assume the electric charge before inserting the dielectric is Q.As soon after we insert the dielectric the electric field reduces to E/K. This also causes a decrease in potential between the plates of the capacitor by the factor K. Thus it will be V/K. Since the capacitor should be at the same potential as the battery always the battery wills send an charge equivalent to KQ in order to maker the potential same as before, And thus the Electric field also will again increase from E/K to E as before. Am I correct????