Why for a metal i.e, conductor dielectri constant is infinity ?

I think such a way that k=Eo/E. So in side a conductor or a metal E=0. So K=0. But E is not 0 all over the conductor i mean from the surface to outer medium.

Am i correct to think in such a way ? What's the correct reason ?

Raghunath Yadav Karike, 13 years ago

Grade:12

2 Answers

SAGAR SINGH - IIT DELHI

878 Points

13 years ago

Dear student,

The dielectric constant is related to the electronic susceptance in an isotropic material.
The susceptance is basically the ratio of polarization to applied electric field.
You can think about a conductor as having "bound" electrons in that they cannot leave the entire material, but are free to polarize across the entire length of a conductor.
When you apply an external electric field to a conductor, you polarize the entire conductor, such that the polarization causes the electric field inside the conductor to be zero (electrostatic equilibrium). In a normal dielectric, the bound electrons cannot move as far as in a conductor, they have a much smaller polarization.
The definition of a dipole moment is charge separation times separation distance.
In a conductor, the induced dipoles have distances of the magnitude of the size of the macroscopic object, which is much much larger than the dipole distances of a dielectric.
Hence, the polarization vectors in a conductor are nearly infinite compared to the polarization vectors of a dielectric (whose order of magnitude we are accustomed to dealing with). The susceptance is therefore near infinite, and so is the relative permittivity.

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Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

Rabik John

33 Points

6 years ago

Relative permitivity is the insulating property of a medium and it reduces force between two point charges ,As metals are conductors and perfect conductors have no resistance so they have infinite permitivity