State and explain Coulomb's law.

Explanation

Coulomb.s law : It states that, the magnitude of electric force between two-point charges at rest, is directly proportional to product of the magnitude of the charges and is inversely proportional to the square of the distance between them.

Consider two charges `q_(1) and q_(2)` separated by distance r.
According to Coulomb.s law
`F prop (q_(1)q_(2))/r^(2) or F= k (q_(1)q_(2))/r^(2)`
Where K is a constant of proportionality, its value depends upon the nature of medium and system of units.
In `SI" "K = 1/4pivarepsilon, "where" ε =` permittivity of medium
So,`" "F = 1/(4pivarepsilon)(q_(1)q_(2))/r^(2)`, when the charges are in vacuum,then `K = 1/4pivarepsilon_(0)`
So,`" " F = 1/(4pivarepsilon_(0))` ,where so = permittivity of tree space `= 8.85 xx 10^(-12)N^(-1)m^(-2)C^(2)`.