When a dielectric slab fills the gap in a parallelplate capa

When a dielectric slab fills the gap in a parallel-plate capacitor, what is the sign of the induced charge next to the negatively charged plate?

Solution

when a dielectric is placed in a uniform electric field , molecules are partially aligh with the field and becomes polarized.

This polarization causes an induced charge on the opposite side.

Hence, the induced charge on negative plate is positive.