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Also known as: electronic attraction, law of electrostatic attraction
Written and fact-checked by
The Editors of Encyclopaedia Britannica
Coulomb’s law, mathematical description of the electric force between charged objects. Formulated by the 18th-century French physicist Charles-Augustin de Coulomb, it is analogous to Isaac Newton’s law of gravity.
Both gravitational and electric forces decrease with the square of the distance between the objects, and both forces act along a line between them. In Coulomb’s law, however, the magnitude and sign of the electric force are determined by the electric charge, rather than the mass, of an object. Thus, charge determines how electromagnetism influences the motion of charged objects. Charge is a basic property of matter. Every constituent of matter has an electric charge with a value that can be positive, negative, or zero. For example, electrons are negatively charged, and atomic nuclei are positively charged. Most bulk matter has an equal amount of positive and negative charge and thus has zero net charge.
Britannica Quiz
Physics and Natural Law
According to Coulomb, the electric force for charges at rest has the following properties:
Like charges repel each other; unlike charges attract. Thus, two negative charges repel one another, while a positive charge attracts a negative charge.
The attraction or repulsion acts along the line between the two charges.
The size of the force varies inversely as the square of the distance between the two charges. Therefore, if the distance between the two charges is doubled, the attraction or repulsion becomes weaker, decreasing to one-fourth of the original value. If the charges come 10 times closer, the size of the force increases by a factor of 100.
The size of the force is proportional to the value of each charge. The unit used to measure charge is the coulomb (C). If there were two positive charges, one of 0.1 coulomb and the second of 0.2 coulomb, they would repel each other with a force that depends on the product 0.2 × 0.1. Thus, if each of the charges were reduced by one-half, the repulsion would be reduced to one-quarter of its former value.
FAQs
Like charges repel; opposite charges attract. The force is proportional to the magnitude of the charges and inversely proportional to the square of the distance between them.
What is the Coulomb's law and its definition? ›
The law states that the magnitude, or absolute value, of the attractive or repulsive electrostatic force between two point charges is directly proportional to the product of the magnitudes of their charges and inversely proportional to the squared distance between them.
What are the facts about Coulomb's law? ›
The size of the force varies inversely as the square of the distance between the two charges. Therefore, if the distance between the two charges is doubled, the attraction or repulsion becomes weaker, decreasing to one-fourth of the original value.
What is Coulomb's law quizlet? ›
Coulomb's law. electric force between charged objects depends on the distance between the objects and the magnitude of the charges.
What is Coulomb's law in words Grade 12? ›
Definition in words: Coulomb's law states that, the electrostatic force exerted by one point charge (Q1) on another point charge (Q2) is directly proportional to the product of the two charges and inversely proportional to the square of the distance (r) between them.
What does Coulomb's stand for? ›
A coulomb (C) is the standard unit of electric charge in the International System of Units (SI). It is the amount of electricity that a 1-ampere (A) current carries in one second (s).
What is an example of Coulomb's law in real life? ›
Another example of Coulomb's law is the comb and small pieces of paper. When a comb is rubbed against the hair, it gets charged. This charged comb can attract small pieces of paper that have opposite charges. Mixing substances in the water also follow Coulomb's law.
What are the 3 parts of Coulomb's law? ›
Coulomb's Law Equation
where Q1 represents the quantity of charge on object 1 (in Coulombs), Q2 represents the quantity of charge on object 2 (in Coulombs), and d represents the distance of separation between the two objects (in meters).
What are the two importance of Coulomb's law? ›
The coulomb's law obeys the principle of superposition, which means that the force between two particles is not affected by the presence of other charges. This principle is used to find the net force exerted on a given particle by other charged particles.
What is true about Coulomb's law? ›
Note that Coulomb's law applies only to charged objects that are not moving with respect to each other. The law says that the force is proportional to the amount of charge on each object and inversely proportional to the square of the distance between the objects.
Coulomb's law correctly describes the electric force that binds the protons and neutrons in the nucleus of an atom. Explanation: The nuclear force is what holds protons and neutrons together in an atom's nucleus.
What is the Coulomb's constant explained? ›
The Coulomb Constant — like many universal constants — gives the value of a quantity (Force) when all of the other factors are one (1). One unit of charge (+ or -) times One unit of charge (+ or -) divided by one unit of distance squared. It also cleans up all the various units.
What is Coulomb force also called? ›
Coulomb force, also called electrostatic force or Coulomb interaction, attraction or repulsion of particles or objects because of their electric charge.
What is Coulomb's law full definition? ›
According to Coulomb's law, the force of attraction or repulsion between two charged bodies is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. The mathematical expression for Coulomb's law, F = Kq 1 q 2 r 2.
What are the basics of Coulomb's law? ›
Coulomb's law describes the strength of the electrostatic force (attraction or repulsion) between two charged objects. The electrostatic force is equal to the charge of object 1 times the charge of object 2, divided by the distance between the objects squared, all times the Coulomb constant (k).
What is Coulombs law in one sentence? ›
Coulomb's Law states that the electrostatic force between two stationary charged particles is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
What is Coulomb's law simple chemistry? ›
When unlike charges (one negative and the other positive) attract each other, or like charges (both positive or both negative) repel each other, Coulomb's law governs the force between them. According to this law the force of attraction or repulsion varies inversely with the square of the distance between the charges.
What is the state Coulomb's law? ›
According to Coulomb's law, the magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them. The force is along the straight line joining them.
What is the Coulomb force explained? ›
Coulomb's Law
According to this law, the force between the two particles is stated in the following manner: Electrostatic force varies proportionally with the product of the magnitude of the charges. Varies inversely with the square of the distance between the two equal and opposite charges.
