Question

Why electric field inside a dielectric decreases due to polarization?

Answer 1

The electric field inside a dielectric material decreases due to polarization because of the way the dielectric responds to the applied external electric field.

Here’s the step-by-step explanation:

1. Polarization in Dielectric: When a dielectric material is placed in an electric field, the positive and negative charges within the molecules (or atoms) of the dielectric shift slightly. This movement creates small dipoles (separation of positive and negative charge) even in materials that don’t normally have them.
   

1. Opposing Electric Field from Dipoles: These induced dipoles produce their own electric field, but this field is in the opposite direction to the applied external electric field. This happens because the positive charges of the dipoles are pulled in the direction of the electric field, while the negative charges are pushed in the opposite direction.
   

1. Resulting Effect: The induced electric field from the dipoles partially cancels out the external electric field inside the dielectric. This means the net electric field inside the dielectric is weaker than the applied field.
   

1. Dielectric Constant: The degree to which the dielectric reduces the electric field depends on its polarizability (how easily its molecules can become polarized) and is described by the material’s dielectric constant. The higher the dielectric constant, the greater the reduction in the electric field.
   

In simpler terms, the polarization causes the dielectric to create its own opposing electric field, which weakens the overall electric field inside the material. This is why the electric field inside a dielectric is always less than the electric field outside or in a vacuum under the same conditions.