Electric Force: Difference between revisions

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--[[User:Asaxon7|Asaxon7]] ([[User talk:Asaxon7|talk]]) 00:48, 18 November 2015 (EST) Claimed by Alayna Saxon
== Claimed by Azan Khan — Fall 2025 ==


This page contains information on the electric force on a point charge. Electric force is created by an external [[Electric Field]].
Introduction:
The electric force is one of the four fundamental interactions of nature. It describes how charged objects push or pull on each other. This page explains the physical meaning of electric force, how to calculate it using Coulomb’s Law, and how the force behaves in real-world situations. The goal is to give students an intuitive and mathematical understanding of the concept as used in Physics 2.


==The Coulomb Force Law==
== Key Concepts ==


The formula  for the magnitude of the electric force of two point charges is:
* Like charges repel and opposite charges attract.
* The electric force acts along the line connecting the two charges.
* The magnitude of the force depends on the size of the charges and the distance between them.
* The force decreases with the square of the distance (inverse-square law).


<math>|\vec F|=\frac{1}{4 \pi \epsilon_0 } \frac{|{q}_{1}{q}_{2}|}{r^2} </math>
== Coulomb’s Law ==


where '''<math>{q}_{1}</math>''' and '''<math>{q}_{2}</math>''' are the magnitudes of charge of point 1 and point 2.
The electric force between two point charges is:


===A Mathematical Model===
F = k * |q1 q2| / r^2


What are the mathematical equations that allow us to model this topic.  For example <math>{\frac{d\vec{p}}{dt}}_{system} = \vec{F}_{net}</math> where '''p''' is the momentum of the system and '''F''' is the net force from the surroundings.
where:


===A Computational Model===
F = electric force (Newtons)


How do we visualize or predict using this topic. Consider embedding some vpython code here [https://trinket.io/glowscript/31d0f9ad9e Teach hands-on with GlowScript]
k = 8.99×10^9 N·m²/C² (Coulomb’s constant)


==Examples==
q1, q2 = the two point charges


Be sure to show all steps in your solution and include diagrams whenever possible
r = distance between the charges


===Simple===
== Vector Form of the Electric Force ==
===Middling===
===Difficult===


==Connectedness==
Electric force has direction. The vector equation is:
#How is this topic connected to something that you are interested in?
#How is it connected to your major?
#Is there an interesting industrial application?


==History==
⃗F₁₂ = k * (q₁ q₂ / r²) * r̂₁₂


Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
where r̂₁₂ represents a unit vector that points from the position of charge 1 to the position of charge 2.


== See also ==
== Common Misconceptions ==


Are there related topics or categories in this wiki resource for the curious reader to explore?  How does this topic fit into that context?
* The electric force is NOT zero just because the net charge is zero.
* The force is not "shared" between charges — each charge experiences its own force.
* Coulomb’s Law applies only to point charges or spherically symmetric charge distributions.


===Further reading===
== Real-World Examples ==


Books, Articles or other print media on this topic
* Static electricity on clothing is caused by attraction between oppositely charged areas.
* Lightning forms when electric forces overcome air resistance.
* Electric forces guide the motion of electrons inside circuits.


===External links===
[[File:CoulombsLawDiagram.png|400px|thumb|Diagram of electric force between charges (public domain).]]


Internet resources on this topic
https://upload.wikimedia.org/wikipedia/commons/thumb/0/02/CoulombsLawDiagram.png/640px-CoulombsLawDiagram.png


==References==
== Interactive Simulation ==


This section contains the the references you used while writing this page
Below is a GlowScript model showing the electric force between two charges.


[[Category:Which Category did you place this in?]]
<iframe src="https://trinket.io/embed/glowscript/31d0f9ad9e" width="100%" height="500"></iframe>
 
Practice Problems
 
Problem 1:
Two charges of +3 μC and –2 μC are separated by 0.40 m. Find the magnitude of the electric force between them.
F = k * |q1 q2| / r^2
F = (8.99×10^9) * (3×10^-6)(2×10^-6) / (0.40)^2
F = 0.34 N
 
Problem 2:
Two electrons are separated by 1 nm. What is the electric force between them?
F = k * e^2 / r^2
F = (8.99×10^9) * (1.6×10^-19)^2 / (1×10^-9)^2
F = 2.3×10^-10 N
 
== Sources ==
 
* OpenStax University Physics (Public Domain)
* HyperPhysics (Public Domain)
* Wikimedia Commons (Public Domain Images)

Latest revision as of 11:32, 28 November 2025

Claimed by Azan Khan — Fall 2025

Introduction: The electric force is one of the four fundamental interactions of nature. It describes how charged objects push or pull on each other. This page explains the physical meaning of electric force, how to calculate it using Coulomb’s Law, and how the force behaves in real-world situations. The goal is to give students an intuitive and mathematical understanding of the concept as used in Physics 2.

Key Concepts

  • Like charges repel and opposite charges attract.
  • The electric force acts along the line connecting the two charges.
  • The magnitude of the force depends on the size of the charges and the distance between them.
  • The force decreases with the square of the distance (inverse-square law).

Coulomb’s Law

The electric force between two point charges is:

F = k * |q1 q2| / r^2

where:

F = electric force (Newtons)

k = 8.99×10^9 N·m²/C² (Coulomb’s constant)

q1, q2 = the two point charges

r = distance between the charges

Vector Form of the Electric Force

Electric force has direction. The vector equation is:

⃗F₁₂ = k * (q₁ q₂ / r²) * r̂₁₂ 

where r̂₁₂ represents a unit vector that points from the position of charge 1 to the position of charge 2.

Common Misconceptions

  • The electric force is NOT zero just because the net charge is zero.
  • The force is not "shared" between charges — each charge experiences its own force.
  • Coulomb’s Law applies only to point charges or spherically symmetric charge distributions.

Real-World Examples

  • Static electricity on clothing is caused by attraction between oppositely charged areas.
  • Lightning forms when electric forces overcome air resistance.
  • Electric forces guide the motion of electrons inside circuits.
File:CoulombsLawDiagram.png
Diagram of electric force between charges (public domain).

https://upload.wikimedia.org/wikipedia/commons/thumb/0/02/CoulombsLawDiagram.png/640px-CoulombsLawDiagram.png

Interactive Simulation

Below is a GlowScript model showing the electric force between two charges.

<iframe src="https://trinket.io/embed/glowscript/31d0f9ad9e" width="100%" height="500"></iframe>

Practice Problems

Problem 1: Two charges of +3 μC and –2 μC are separated by 0.40 m. Find the magnitude of the electric force between them. F = k * |q1 q2| / r^2 F = (8.99×10^9) * (3×10^-6)(2×10^-6) / (0.40)^2 F = 0.34 N

Problem 2: Two electrons are separated by 1 nm. What is the electric force between them? F = k * e^2 / r^2 F = (8.99×10^9) * (1.6×10^-19)^2 / (1×10^-9)^2 F = 2.3×10^-10 N

Sources

  • OpenStax University Physics (Public Domain)
  • HyperPhysics (Public Domain)
  • Wikimedia Commons (Public Domain Images)
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