Coulomb's Constant

Definition

Coulomb's constant, also known as the electrostatic constant or the electric force constant, is a fundamental physical constant that describes the strength of the electrostatic force between two point charges. It is a crucial parameter in understanding and quantifying various electrical phenomena, including Coulomb's law, electric fields, electric flux, electric potential energy, and applications of electrostatics.

5 Must Know Facts For Your Next Test

1. Coulomb's constant, denoted as $k_e$, has a value of approximately $8.99 \times 10^9$ N⋅m$^2$/C$^2$.
2. Coulomb's constant is used in the mathematical expression of Coulomb's law, which describes the force of interaction between two point charges.
3. The electric field strength at a given point is directly proportional to Coulomb's constant and the charge at that point, and inversely proportional to the square of the distance from the charge.
4. Coulomb's constant is a crucial parameter in the calculation of electric potential energy, as it appears in the formula for the potential energy of a system of charges.
5. The applications of Coulomb's constant span various areas of electrostatics, including the design and analysis of electrical circuits, the study of charged particles in particle accelerators, and the understanding of the behavior of charged objects in the environment.

Review Questions

• Explain how Coulomb's constant is used in Coulomb's law and describe the relationship between the variables in this law.
  • Coulomb's constant, $k_e$, is a fundamental physical constant that appears in the mathematical expression of Coulomb's law. Coulomb's law states that the force of interaction between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Specifically, the force between two charges $q_1$ and $q_2$ separated by a distance $r$ is given by the equation $F = k_e \frac{q_1 q_2}{r^2}$. The value of Coulomb's constant, approximately $8.99 \times 10^9$ N⋅m$^2$/C$^2$, determines the strength of the electrostatic force between the charges.
• Describe the role of Coulomb's constant in the calculation of electric field strength and explain how it is used in this context.
  • Coulomb's constant, $k_e$, is a crucial parameter in the calculation of electric field strength. The electric field strength at a given point is directly proportional to Coulomb's constant and the charge at that point, and inversely proportional to the square of the distance from the charge. Mathematically, the electric field strength $E$ created by a point charge $q$ at a distance $r$ is given by the equation $E = k_e \frac{q}{r^2}$. The value of Coulomb's constant determines the magnitude of the electric field, which is a vector field that describes the force experienced by a test charge at that point in space due to the presence of other charges.
• Analyze the importance of Coulomb's constant in the context of electric potential energy and explain how it is used in the calculation of this quantity.
  • Coulomb's constant, $k_e$, is a fundamental parameter in the calculation of electric potential energy. The potential energy of a system of charges is directly proportional to Coulomb's constant and the product of the charges, and inversely proportional to the distance between them. Specifically, the potential energy $U$ of a system of two charges $q_1$ and $q_2$ separated by a distance $r$ is given by the equation $U = k_e \frac{q_1 q_2}{r}$. The value of Coulomb's constant, along with the charges and their separation, determines the potential energy of the system, which is a scalar field that describes the work required to move a test charge from infinity to a given point in the electric field. Understanding the role of Coulomb's constant in electric potential energy is crucial for analyzing the behavior of charged particles and the energy requirements in various electrostatic applications.

Related terms

Coulomb's Law: Coulomb's law is a fundamental principle in electrostatics that describes the force of interaction between two point charges, which is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

Electric Field: The electric field is a vector field that describes the force experienced by a test charge at a given point in space due to the presence of other charges. Coulomb's constant is a key parameter in the mathematical expression of the electric field.

Electric Flux:

Electric flux is a measure of the total electric field passing through a given surface, and Coulomb's constant is a factor in the calculation of electric flux.