What is the Difference Between Coulomb’s Law and Gravitational Law

The key difference between Coulomb’s law and gravitational law is that Coulomb’s law describes the force between the charges, whereas gravitational law describes the force between the masses.

There are many different important laws and theories in physical chemistry which have applications in all different fields of chemistry. Coulomb’s law and gravitational law are two such laws.

CONTENTS

1. Overview and Key Difference
2. What is Coulomb’s Law 
3. What is Gravitational Law
4. Similarities – Coulomb’s Law and Gravitational Law
5. Coulomb’s Law vs Gravitational Law in Tabular Form
6. Summary – Coulomb’s Law vs Gravitational Law 

What is Coulomb’s Law?

Coulomb’s law is an experimental law that can quantify the amount of force between two stationary, electrically charged particles. It is also known as Coulomb’s inverse-square law. It is a law in physics and physical chemistry.

An electric force between charged bodies at rest is conventionally called electrostatic force or Coulomb force. However, this law was published after some time after its discovery, and the law was first published by the French physicist Charles-Augustin de Coulomb. This law was an essential component in developing the theory of electromagnetism. This is because it makes it easy to discuss the quantity of electric charge in a meaningful way.

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 equation for this law can be given as below:

F = K(q₁.q₂/r²)

Where F is the force, K is the Coulomb’s constant, q1 and q2 are signed magnitudes of the charges, and the scalar “r” is the distance between the charges. The force acts along a straight line, which joins the two charges. The charges have the same sign, and the electrostatic force between them is repulsive. If the signs are different from each other, the force between them is attractive.

What is Gravitational Law?

Gravitational force can be described as the force that acts on an object due to gravity. Gravity or gravitation is a natural process observed in all things with a mass or energy, for example, planets, stars, galaxies, and light. Gravitational force is the weakest force among the four fundamental interactions of physics (the other three forces are the strong interaction, electromagnetic force, and weak interaction). Therefore, gravitational force does not have considerable influence at the level of subatomic particles. However, it is the dominant interaction force at the macroscopic level that causes the formation, shape, and trajectory of astronomical bodies.

We can define gravitational force as a force that attracts any two objects having a particular mass. We call it an attractive force because it always causes the two masses to pull together and never pushes them apart. Newton’s universal law of gravitation expresses that every object with a mass pulls on every other object in the universe. However, this attraction force largely depends on the mass of the object; e.g., large masses show massive attractions.

What are the Similarities Between Coulomb’s Law and Gravitational Law?

1. Coulomb’s law and Gravitational law describe conservative forces
2. Both describe attractions and repulsions between objects.

What is the Difference Between Coulomb’s Law and Gravitational Law?

Coulomb’s law and gravitational law are two important laws in chemistry. The key difference between Coulomb’s law and gravitational law is that Coulomb’s law describes the force between the charges, whereas gravitational law describes the force between the masses.

The below infographic presents the differences between Coulomb’s law and gravitational law in tabular form for side-by-side comparison.

Summary – Coulomb’s Law vs Gravitational Law

Coulomb’s law is an experimental law that can quantify the amount of force between two stationary, electrically charged particles, while gravitational force is the force that acts on an object due to gravity. The key difference between Coulomb’s law and gravitational law is that Coulomb’s law describes the force between the charges, whereas gravitational law describes the force between the masses.

Reference:

1. “Newton’s Law of Gravitation.” Encyclopædia Britannica, Encyclopædia Britannica, Inc.

Image Courtesy:

1. “Coulombs Law” By User:Dna-Dennis (CC BY 3.0) via Commons Wikimedia
2. “Earth-G-force” By Dake (Slice earth.svg)derivative work: KronicTOOL (talk); Software: Photoshop – Slice earth.svg (CC BY-SA 2.5) via Commons Wikimedia