Question

Define Coulomb's law and its role in electrostatics.

Answer 1

Coulomb's law is a fundamental principle in physics that describes the electrostatic force between two electrically charged particles. It is named after the French physicist Charles-Augustin de Coulomb, who first formulated it in the late 18th century.

The law states that the force of attraction or repulsion between two point charges is directly proportional to the product of their magnitudes (q1 and q2) and inversely proportional to the square of the distance (r) between them. Mathematically, Coulomb's law is expressed as:


=

⋅
∣

1
⋅

2
∣

2
F=
r
2
k⋅∣q
1
    ​

⋅q
2
    ​

∣
    ​


Where:


F is the electrostatic force between the two charges (in newtons, N).

k is Coulomb's constant, which depends on the medium between the charges and is approximately
8.99
×
1
0
9
 
N
⋅
m
2
/
C
2
8.99×10
9
N⋅m
2
/C
2
 in vacuum.

1
q
1
    ​

 and

2
q
2
    ​

 are the magnitudes (or absolute values) of the two point charges (in coulombs, C).

r is the distance between the two charges (in meters, m).

Key points regarding Coulomb's law and its role in electrostatics:

Force between Charges: Coulomb's law describes the force of interaction between two charged particles. Like charges (both positive or both negative) repel each other, while opposite charges (positive and negative) attract each other.

Inverse-Square Relationship: The force between two charges decreases rapidly with an increase in the distance between them. Specifically, the force is inversely proportional to the square of the distance between the charges. This means that doubling the distance will result in only one-fourth the force, and so on.

Vector Nature: Coulomb's law is a vector equation, which means it considers both the magnitude of the force and its direction. The force is along the line joining the charges, repulsive if both charges have the same sign, and attractive if they have opposite signs.

Superposition Principle: Coulomb's law obeys the superposition principle, which means that the total force on a charge due to multiple other charges is the vector sum of the forces between the individual pairs of charges.

Importance in Electrostatics: Electrostatics is the study of stationary electric charges and their interactions. Coulomb's law is the foundation of electrostatics as it governs how charged particles behave and interact in a static electric field. It helps understand phenomena such as the behavior of conductors and insulators, the formation of electric fields, the behavior of charged particles in capacitors, and many other aspects of electrostatics.

Overall, Coulomb's law plays a crucial role in understanding and predicting the behavior of electrically charged particles, and it has wide applications in various areas of physics and engineering.