Coulomb's Laws of Electrostatics describe the fundamental principles governing the interaction between electric charges. These laws were formulated by French physicist Charles-Augustin de Coulomb in the late 18th century and are fundamental to the field of electrostatics. There are two main laws:
Coulomb's First Law (Law of Electrostatic Attraction and Repulsion):
The magnitude of the electrostatic force between two point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. Mathematically, this can be expressed as:
=
1
2
2
F=k
r
2
q
1
q
2
Where:
F is the magnitude of the electrostatic force between the charges.
k is Coulomb's constant, a proportionality constant that depends on the medium between the charges. In vacuum,
k is approximately
8.9875
×
1
0
9
N m
2
/
C
2
8.9875×10
9
N m
2
/C
2
.
1
q
1
and
2
q
2
are the magnitudes of the two point charges.
r is the distance between the charges.
Coulomb's Second Law (Principle of Superposition):
The net electrostatic force on a charged particle due to a group of other charges is the vector sum of the individual forces exerted by those charges. In mathematical terms, if
1
F
1
,
2
F
2
, ...,
F
n
are the individual electrostatic forces on a charge
q due to charges
1
q
1
,
2
q
2
, ...,
q
n
, respectively, then the total force
F on
q is given by:
=
1
+
2
+
…
+
F=F
1
+F
2
+…+F
n
This law allows us to analyze systems with multiple charges and determine the resultant force on a particular charge.
Coulomb's Laws of Electrostatics are essential for understanding how electric charges interact and how electric fields are generated. They serve as the foundation for many principles and applications in electrostatics and electromagnetism, including the behavior of conductors, insulators, and capacitors, as well as the formation of electric fields and potential energy.