0

We all know about the value of permittivity of free space but is this actually enough of for our knowledge? We should be taught that what actually does permittivity of free space means.

Qmechanic
  • 201,751
kunal aggarwal
  • 11
  • 4
    Where is the question? This seems more to be more like an "I believe the education system is wrong"-comment than a question. Could you please reformulate? – Martin Mar 19 '15 at 11:25

4 Answers4

4

The product of the permittivity and permeability is encoded into the geometry of spacetime because the product $\varepsilon_0\mu_0 = 1/c^2$ and the speed of light is special. So the value of the product is telling us about the geometry of spacetime.

The relative values of $\varepsilon_0$ and $\mu_0$ tell us about the relative strengths of the electric and magnetic fields, or you can look at it another way and say the relative values of $\varepsilon_0$ and $\mu_0$ tell us how the electromagnetic field splits into electric bits and magnetic bits.

I don't know of any fundamental reason why $\varepsilon_0$ and $\mu_0$ should have the relative values that they do, except that if the values changed much intelligent life probably wouldn't be around to comment on the fact.

Community
  • 1
John Rennie
  • 355,118
0

The question is apt enough. It is called that permittivity of a medium is a measure of the resistance offered by it to creation of electric field in it. And it is related to polarization of the medium in presence of electric field. That's perceptible enough. But when we come to absolute vacuum, who is offering any resistance? Or what is getting polarized?

Durjoy Chakraborty
  • 26
0

Permittivity and permeability of free space are an artefact of the SI system of units, whete permittivity and permeability are dimensional quantities.

In mamy other systems of units, e.g., in CGS system, the permittivity and permeability are dimensionless, and their values for vacuum are taken to be $1$. The price to pay is the speed of light appearing explicitly in the Maxwell equations.

Remark In particular, the Wikipedia article on Maxwell equations provides the formulas in both systems of units, the cgs ones being arguably more physically transparent.

Roger V.
  • 58,522
0

Permittivity is simply how much electric field a medium allow to pass through it. Allowed field is inversely proportional to permittivity. so in the case of conductors where permittivity is infinite there is zero penetration of electric field.Unfortunately zero permittivity for free space is not allowed as it would lead to singularity in speed of light and force between particles.

Mubashir
  • 117
  • 6