Question

define relative permittivity of a medium meritnation

Answer 1

Relative permittivity e(r) is defined as the ratio of absolute permittivity of a medium (e) to the absolute permittivity of free space (e0)

e(r) = e / e0

It can also be defined as the the ratio of forces of attraction/repulsion between two point charges separated by a certain distance in vacuum to the force of attraction when they are placed in a medium same distance apart.

e(r) = F(o) / F(medium)

Clearly relative permittivity is a unitless constant.

Force between two charges is maximum when they are placed in vacuum.

In your second part, force in vacuum should be 100 N and that in medium be 10 N

such that relative permittivity = 100 / 10 = 10

Answer 2

Relative Permitivity:

1) The Relative Permitivity of a medium is its (absolute permitivity) permitivity expressed as a ratio relative to the permitivity of vacuum.

2) Permitivity is the material property that affects the Coulomb force between two point charges in the material .

3) Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum.