Uniform field between plates
Between two parallel charged plates the field is steady and equals voltage divided by plate gap, E = V/d.
Last updated
Analogy
A smooth slope where the force is the same everywhere.
Example
E = V / dE = 100 / 0.01E = 10,000 V/m
In practice
100 V across a 1 cm gap gives a field of 10,000 V/m.
Practice
Flashcards
- What is the field between parallel plates?E = V/d, uniform.
Interview questions
- Compare electric field and electric potential, and show how they are related for parallel plates.
- Field is a vector, potential is a scalar
- E = V/d
- Field points from high to low potential
Questions people ask
Why is the field uniform between plates?
Each large flat sheet makes a field that does not change with distance, and the fields from two opposite sheets add between them and cancel outside. This holds well near the middle of the plates when the gap is small compared with the plate size.
How do I find an electron's path between plates?
The force qE is constant, so the electron has constant acceleration a = eE/m toward the positive plate. If it enters sideways, the path is a parabola, just like a projectile under gravity. This is how old oscilloscope screens steered their electron beams.