Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.
The Electric Field
- The electric field is simply a label attached to every point
in space. It gives the magnitude and direction of the
electric force which a charge of +1 Coulomb would experience
at that point.
- One can measure the electric field directly by observing
the electric force on a little test charge at different
locations.
- The electric field is defined as
electric force Newtons
E = ------------- -------
charge Coulomb
- One can calculate the electric field due to a point
charge:
charge
E = k * ------------
(distance)^2
- The electric field lines point away from a positive charge
(because a charge of +1 C would move away from it)
and toward a negative charge
(because a charge of +1 C would move toward it).
- The electric fields due to several particles simply add together
in a vector sense (component by component).
- One can calculate the electric field between two uniformly
charged plates (which are much larger than the distance between them):
Q
E = --------
eps * A
where
Q = magnitude of the charge on each plate
eps = permittivity of free space
= 8.854 x 10^(-12) C^/N-m^2
A = area of each plate
The electric field between parallel plates doesn't depend on the
distance away from either plate.
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Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.