Question

Is there any term in this chapter name dielectric ?
What is relative permittivity?

Answer 1

relative permitivity is the ratio of permitivity of medium to permitivity of free space, i.e. it is the comparision of how coulomb force acts on a charge in medium to that of a charge placed in free space .

and the term dielectric means a material type that develops charges inside its volume or on surface when placed in external electric field and the bound charges opposes the field inside the material.