A dielectric slab of thickness d is inserted in a parallel plate capacitor whose negative plate is at x=3d. The slab is equidistant from the plates. The capacitor is given some charge. As x goes from 0 to 3d :
- the magnitude of the electric field remains the same
- the direction of the electric field remains the same
- the electric potential increases continuously
- the electric potential increases at first, then decreases and again increases