Question

I do not understand what epsilon sub 0 is, nor epilsion ... What does "permittivity of free space" mean?

Answer 1

\(\epsilon_{0}\) can be thought of the scaling constant when experiments determined that electrostatic forces of an isolated charge is proportional to the magnitude of the charge and one over r squared proportional to the distance from the said charge in vacuum.

\(\epsilon\) can then be thought of as the resistance of setting up the electric field in another material.

Answer 2

Electric permittivity is physical quantity that describe how an electric field affects and is affected by a medium . It is determined by the ability of a material to polarise in response to an applied field and thereby to cancel , partially , the field inside the material . Similarly magnetic permeability is the ability of a substance to acquire magnetisation in magnetic fields . Its a measure of the extent to which magnetic field can penetrate a matter .
As we know Gravitational force do not depend on the intervening medium while the electomagnetic force depends on the medium between the two charges or magnets . Hence while G is a universal constant , while permittivity and permeability depends on the medium ,. They have different value for different media
The product of permittivity and permeabilty turns out to be related to the speed v of electomagnetic radiation in the medium through permittivityxpermeablity= 1/v^2