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# Tag Archives: polarization

## How does dielectric constant depend on nature of medium?

How does dielectric constant depend on nature of medium?
Does this have any relation with free electrons and force between molecules?

-Vaanya Asked

Answer:

Dielectric Constant, also called relative permitivity of a medium depends on the electric susceptibility of it, the ease with electric flux lines can pass through it.

The susceptibility depend on molecular polarization, the electric dipole moment acquired per unit volume in an external electric field.

So, the thing to note is that, dielectric constant is a physical quantity measured as a comparison of the strength of electric field in vacuum to that inside the material.

Dielectric constant can be defined in terms of electrostatic force

$K=\frac{F_{0}}{F_{m}}$

Dielectric Constant can also be defined in terms of capacitance.

$K=\frac{C_{m}}{C_{0}}$

Please visit the following links for more information.

## Electric Field due to Polarisation

Sreeram asks:

“do charges produced due to polarization in a dielectric produce electric field outside?”

Ans:

When a dielectric is kept in an electric field, it is polarized. The polarized ends are just like the two plates of a parallel plate capacitor. The electric field is confined between the two surfaces (except for some edge effect). So, in a macroscopic point of view, the answer is no.

(However, I agree that there is scope for disagreement and debate when we think and look at the microscopic level. Users of the site are requested to post comments)

## What is the principle used in the working of 3D glasses?

Sreeda asked:

What is the principle used in the working of 3D glasses?

Answer.

3D glasses are actually polaroids. They are not creating the 3D effects. The 3 D movies are filmatographed with two cameras help at two different angles just like we see with TWO eyes.

The two films are projected on the screen with polarized light with their plane of polarization in perpendicular to each other. If we look at the screen without ant 3D glass we will see blurred images only as the two pictures are overlapping each other and both the image are seen together by both the eyes.

3D glasses use Polaroid with the plane of polarization in mutually perpendicular directions. So, when we wear the Polaroid glasses and look at the screen, only one of the image will be seen by one of the eyes and the second eye sees the other image. This creates the 3D sensation, we are seeing the image filmed with the left camera with the left aye and that with the right camera with right eye.

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