Coulombs law

Generally we know that a charge attracts another charge or repels another charge.  Attraction or repulsion depends upon three terms. These are(1)   the distance between two charges
(2)   the amount of two charges
(3)   medium between two charges.
French scientist coulomb explained a law based on given conditions acting between two charges in 1787. The law is called coulomb’s law. At first we need to learn about point charge which will need quite often.

# Point charge: when the dimension of charged body is very small then the charged body is known as point charge. Small charged bodies are compared according to the distances between then and they are considered as mathematical points.
Now it will become easy to learn coulomb’s law.

# Coulomb’s law: The magnitude of attractive or repulsive force between two point charges is directly proportional to the product charges and inversely proportional to the distance of two charges. The force acts as a straight line joining the two charges.
#Explanation of coulomb law:


Let,
Two point charges are q₁and q_2,
The distance between two point charges is r.
Consider they assert force of magnitude F.
According to coulomb’s law,

_Here q₁and q₂ are constant.
At the time of varying q₁, q₂ and r. we get from equation (i) and (ii),

Here k is a constant of proportionality. The values of k depend upon the nature of medium and units of q₁, q_2, r and F.