Permittivity (background reading from Wikipedia)

[jeff1evesque]

Background reading from Wikipedia
I read the following from Wikipedia,

"Permittivity is a physical quantity that describes how an electric field affects, and is affected by, a dielectric medium, and is determined by the ability of a material to polarize in response to the field, and thereby reduce the total electric field inside the material. Thus, permittivity relates to a material's ability to transmit (or "permit") an electric field."

Question
How does a dielectric's dipole becoming polarized

...thereby reduce the electric field inside the material.

 

[berkeman]

Look at the electric field between the separated parts of the dipole... doesn't it go the opposite way of the overall field?

 

[jeff1evesque]

Look at the electric field between the separated parts of the dipole... doesn't it go the opposite way of the overall field?

I am not sure, could you elaborate more. All I know as of now is that dipoles are not necessarily aligned, and when the electric field is applied (I think?), then the dipoles align.

Thanks,


JL

 

[negitron]

Right. In what direction do they align, in terms of polarity, with respect to the applied external E field?

 

[jeff1evesque]

Right. In what direction do they align, in terms of polarity, with respect to the applied external E field?

The negative end of the dipole matches with (in the direction) of positive charges (capacitor or other dipoles)? And between a capacitor, could there be many dipoles spanning the distance between the two plates ?

 

[negitron]

Okay, and when you have one electric field oriented in one direction and another in the opposite one the net field is...?

 

[jeff1evesque]

Okay, and when you have one electric field oriented in one direction and another in the opposite one the net field is...?

Got it, zero (if they are equal-which they are in this situation).

Thanks,Jeff