Coulomb’s law
Coulomb’s law states that “The force exerted between two
points is directly proportional to the product of their strengths, is inversely
proportional to the square of the distance between them.”
This law is also called the Second law of electrostatics.
Scalar Form of Coulomb’s Law:
Where k is the constant of
proportionality, whose value depends on the systems of units employed.
Units
In SI units Force (F) is in newton,
Charge (Q1, Q2) in coulombs, Distance (d) in meters and
Coulomb constant k. Here
is the absolute permittivity and
is the relative permittivity.
One Coulomb
1 coulomb is defined as “An electric
charge placed in air from an equal and similar charge repels it with a force of
9x109 N.”It is commonly used in electric current as micro Coulomb
(μC) and micro micro Coulomb (μμC).
Then the equation becomes:
Consider IF Q1 and Q2
are in coulomb, d in meter, Eo in farad/meter and F is in newton. Then
