Calculate Electric Force of Electron Put in at Point B

This calculator helps you determine the electric force between an electron and another charged particle placed at point B using Coulomb's Law. Understanding this force is fundamental in physics and electronics.

Introduction

When an electron is placed at point B near another charged particle, an electric force is exerted between them. This force can be calculated using Coulomb's Law, which describes the electrostatic interaction between two charged particles.

The electric force depends on the charges of the particles, the distance between them, and the permittivity of the medium. For calculations in a vacuum, the permittivity is the permittivity of free space.

Coulomb's Law Formula

The electric force (F) between two point charges is given by:

F = k * (|q₁q₂|) / r²

Where:

F = electric force (in newtons, N)
k = Coulomb's constant (8.9875 × 10⁹ N·m²/C²)
q₁ and q₂ = charges of the two particles (in coulombs, C)
r = distance between the two charges (in meters, m)

For an electron, the charge (q) is -1.602 × 10⁻¹⁹ C. The force direction depends on the sign of the charges: like charges repel, opposite charges attract.

Worked Example

Let's calculate the electric force between an electron and a proton placed 1 nanometer apart.

Charge of electron (q₁) = -1.602 × 10⁻¹⁹ C
Charge of proton (q₂) = +1.602 × 10⁻¹⁹ C
Distance (r) = 1 × 10⁻⁹ m
Coulomb's constant (k) = 8.9875 × 10⁹ N·m²/C²

F = (8.9875 × 10⁹) × (|(-1.602 × 10⁻¹⁹)(1.602 × 10⁻¹⁹)|) / (1 × 10⁻⁹)²

F = (8.9875 × 10⁹) × (2.567 × 10⁻³⁸) / (1 × 10⁻¹⁸)

F = 2.29 × 10⁻⁸ N

The calculated force is 2.29 × 10⁻⁸ N, which is an attractive force since the charges are opposite.

Interpreting Results

The calculated electric force helps determine:

Whether the force is attractive or repulsive
The magnitude of the force, which affects particle movement
How the force changes with distance (inverse square law)

Note: This calculation assumes the charges are point charges and the medium is a vacuum. In real materials, the permittivity changes, affecting the force.

FAQ

What is Coulomb's Law?

Coulomb's Law describes the electrostatic force between two charged particles. It states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

How does distance affect the electric force?

The electric force decreases with the square of the distance between the charges. Doubling the distance reduces the force to one-fourth of its original value.

What units are used in this calculation?

The calculation uses coulombs (C) for charge, meters (m) for distance, and newtons (N) for force. The Coulomb constant is in N·m²/C².

Can this calculator be used for non-electron charges?

Yes, you can input any charge values in the calculator. The formula applies to any charged particles, not just electrons.