A dielectric slab of thickness `d` is inserted in a parallel plate capacitor whose negative plate is at `x=0` and positive plate is at `x=3d` The slab is equidistant from the plates. The capacitor is given some charge. As one goes from 0 and 3d.

Options

A. the magnitude of the electric field remains the same
B. the direction of the electric field remains the same
C. the electric potential increases continuously
D. the electric potential increases at first, then decreases and again increases

Answer

B, C

Explanation

The magnitude and direction of electric field at different point are shown in figure.

The direction of the electric field remain the same.Hence option (B) is correct similarly.electric line always flow from higher to lower potential, therefore, electric potential increases continuosly as we move from x=0 to x=3d.
Therefore option (C) is also correct.The variation of electric (E) and potential (V) with x will be as follows
`OA||BCand(slope)_(OA)gt(slope)_(AB)`
Because `E_0-d=E_(2d)-3d and E_(0-d)gtE_d-2d`