What is the influance of electric field in a dielectric medium?

Question

An electric field passes through a dielectric medium....lets consider its intensity to be "Z". When this field passes through a dielectric medium what will be its intensity when it emerges out of the dielectric medium; just outside this medium?...in other words....what will be the intensity left when it move out of the medium on the other side?

Z/K?...where K is the dielectric constant

Answer 1

If you are referring to static electric fields, the field does not "move" through the medium, but passes through it. Normally, the field outside the dielectric is not affected by the field inside, but if the field is set up externally to pass through both (by placing the dielectric between two plates at a potential difference), the field outside the dielectric will be K times the field inside the dielectric.

If the potential difference between two parallel plates is V, and their separation is d, the electric field between them is V/d. If you insert a dielectric of thickness r into this arrangement, the electric field in the dielectric Ed is (1/K) times the field outside Eo. The integral of field between the plates must equal the potential difference, so Ed*r + Eo*(d-r) = V. Since Ed = (1/K)*Eo, substitute and solve for Eo and Ed.

The result is Eo = V/[r*(1/K - 1) + d].

You will find that inserting the dielectric will increase the field outside from its value before the dielectric was inserted.