Question

Why is the electric field constant between plates?

Answer 1

Electric field:

1. The term "electric field" refers to a physical field that surrounds electrically charged particles and acts as either an attractor or a repellent on all other charged particles in the field.

Explanation

1. The electric field between the oppositely charged parallel plates is constant.
2. The formula of the electric field generated by a positively charged plate is $E=\frac{Q}{2{\epsilon }_{0}A}$ and the negatively charged plate is $E=-\frac{Q}{2{\epsilon }_{0}A}$
3. Here, $Q$ is the charge of the plate, $A$ is the area of cross-section of the plate and ${\epsilon }_0$ is the permittivity of free space.
4. The direction of electric fields are opposite outside the plates so they cancel each other whereas inside the plate the direction is the same so it becomes $E=\frac{Q}{{\epsilon }_{0}A}$ because the charge on both the plates is the same and opposite and the area of the parallel plates used is approximately the same (as used in the capacitor).
5. The charge on the plates, area, and permittivity remains constant so the electric field inside the plates also remains constant

Thus, the electric field is constant between plates because plates generate a constant electric field in the same direction.