Physics ABC - About Electric Fields 03

Electric Field

The electric field is a physical field that exists around a charges or a changing magnetic field and can transfer the interaction between the charges.

The electric field is different from the ordinary substance. Although it is not composed of molecular and atoms, it is a special substance that exists objectively, with objective properties such as force and energy of ordinary substances.

Electric Field Force: The electric field has a force on the charge that is placed in it, this force is called electric field force. We use ∈(vector) to denote The Electric Field (in some education text books, it is called Electric Filed Intensity or Electric Field Strength). Its unit is N/C or V/m

The relationship between the electric force and electric filed is:

FE(vector) = q∈(vector)

The electric force is thun parallel to ∈(vector), with direction depending on whether the charge is positive or negative.

According to Coulombs Law: FE = k(q1q2) / r^2

We can get ∈(vector) = kq / r^2 (Only applicable to point charges), which means the magnitude of the electric field at a distance r from a point charge q.

The direction of the field strength at a point in the electric field is defined as the direction of the electrostatic force on the positive charge placed at that point.

Uniform electric field strength: E = U/d (D is the distance between two points along the direction of the field strength)

The electric field strength of a point charge is determined by the point charge and has nothing to do with the test charge.

Electric field line

Electric field lines are false curves drawn in order to depict the electric field distribution vividly.

The tangent direction of each point of Electric field lines is the direction of the field strength at that point.

The density of Electric field lines indicates the size of the field strength in that area, where the electric field lines are dense, the field is strong, and vice versa.

The electric field lines of the electric field do not close or intersect, starting from a positive charge (infinity) and ending at a negative charge (infinity).

The electric field lines are perpendicular to the equipotential surface, and the electric potential decreases along the direction of the electric field lines.

The electric field lines of a uniform electric field are parallel.

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Physics ABC - About Electric Fields 01
Physics ABC - About Electric Fields 02
Physics ABC - About Electric Fields 03