Coulomb's law
* An experimental law of physics
* Formulated by French physicist Charles-Augustin de Coulomb.
* Quantifies the amount of force between two stationary, electrically charged particles.
*Gravitational and electric forces decrease with the square of the distance between the objects
* The magnitude and sign of electric force are determined by electric charge.
*Charge determines how electromagnetism influences the motion of charged objects.
*Electrostatic force of attraction or repulsion is directly proportional or inversely proportional.
Properties of Electric force for charges at rest.
*Like charges repel each other; unlike charges attract.
*Two negative charges repel one another
* Positive charge attracts a negative charge.
*The attraction or repulsion acts along the line between two charges.
*The size of the force varies inversely as the square of the distance between the two charges.
*If the distance between the two charges is doubled, the attraction or repulsion becomes weaker.
*The size of the force is proportional to the value of each charge.
Coulomb’s Law Formula
*Q1 and Q2 are the electrical charges of two objects.
*d is the distance between the center of the objects.
*The charged objects are placed in a medium of permittivity εoεr
*This formula allows us to calculate the electrostatic force that two charges exert on each other.
Coulomb’s First Law
* like-charged objects (bodies or particles) repel each other
* unlike charged objects (bodies or particles) attract each other.
Coulomb’s Second Law
*the force of attraction or repulsion between two electrically charged objects is directly proportional to
the magnitude of their charge
* inversely proportional to the square of the distance between them.
Limitations of Coulomb’s Law
*Coulomb’s law is valid, if the average number of solvent molecules between the two interesting charge
particles should be large.
*Coulomb’s law is valid, if the point charges are at rest.
*It is difficult to apply the Coulomb’s law when the charges are in arbitrary shape.