Coulomb's Law

Definition

Coulomb's law is a fundamental principle in electrostatics that describes the force of interaction between two stationary, electrically charged particles. It states that the force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.

5 Must Know Facts For Your Next Test

1. Coulomb's law is a vector equation, meaning the force has both magnitude and direction.
2. The force between two charges is always along the line connecting the two charges.
3. The force between two charges of the same sign (both positive or both negative) is repulsive, while the force between charges of opposite sign is attractive.
4. The magnitude of the force between two charges is inversely proportional to the square of the distance between them.
5. Coulomb's law is valid only for point charges or for charged objects that are much smaller than the distance between them.

Review Questions

• Explain how the magnitude of the force between two charges is related to their charges and the distance between them according to Coulomb's law.
  • According to Coulomb's law, the magnitude of the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. This means that as the charges increase, the force increases proportionally, but as the distance between the charges increases, the force decreases by the square of the distance. For example, if the distance between two charges is doubled, the force between them will decrease by a factor of four.
• Describe the direction of the force between two charges according to Coulomb's law.
  • Coulomb's law states that the force between two charges is a vector quantity, meaning it has both magnitude and direction. The direction of the force is always along the line connecting the two charges. If the charges have the same sign (both positive or both negative), the force between them is repulsive, meaning the charges will push each other apart. If the charges have opposite signs, the force between them is attractive, meaning the charges will pull each other together.
• Analyze how the Superposition Principle relates to Coulomb's law and the calculation of the net electric force on a charge.
  • The Superposition Principle states that the electric field produced by multiple charges is the vector sum of the electric fields produced by each charge individually. This principle, combined with Coulomb's law, allows for the calculation of the net electric force on a charge due to the presence of multiple other charges. To find the net force, one can first calculate the individual forces between the charge of interest and each of the other charges using Coulomb's law, and then add these forces vectorially according to the Superposition Principle. This enables the determination of the magnitude and direction of the net force on the charge, which is essential for understanding the behavior of charged particles in electric fields.

Related terms

Electric Charge:

A fundamental property of matter that can be positive or negative, and is the source of the electric force.

Electric Field:

The region surrounding a charged particle in which a test charge would experience an electric force.

Superposition Principle:

The principle that the electric field produced by multiple charges is the vector sum of the electric fields produced by each charge individually.