Coulomb's Law Force Calculator
Visualize the electrostatic force between two point charges. Adjust charge magnitude, sign, and distance to see attractive/repulsive forces and the inverse-square F vs r graph.
WHAT IS COULOMB'S LAW?
Coulomb's Law describes the magnitude of the electrostatic force between two point charges. The force is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them (). Like charges repel each other, while opposite charges attract, with the force acting along the line connecting the centers of the two charges.
HOW TO USE THIS VISUALIZATION
1. **Change Charge Magnitudes**: Use the sliders to increase or decrease and . Notice how the force vectors (arrows) grow as charge increases. 2. **Adjust Separation**: Drag the charges to change their distance . Observe how the force drops rapidly as they move apart ( relationship). 3. **Toggle Polarity**: Switch the signs of the charges to observe the change from attraction to repulsion.
CORE FORMULAS
AP EXAM CONNECTION
Unit: Unit 3: Electric Force, Field, and Potential (Topic 3.1)
Learning Objective: LO 3.B.1
COMMON MISCONCEPTIONS
- Force between charges doesn't follow Newton's Third Law (it does)
- Electric force is the same as electric field (force is )
KEY TAKEAWAYS
- Electrostatic force follows the inverse-square law.
- Like charges repel, opposite charges attract.
- Electrostatic forces between two charges are always equal and opposite.
- The force increases linearly with the magnitude of each charge.
PRACTICE QUESTIONS
Q1 (QUANTITATIVE): Two point charges and are separated by a distance . If the distance between them is doubled, by what factor does the electrostatic force change?
Show Answer & Explanation
Answer: 1/4 (0.25)
Explanation: Since , doubling the distance () results in a force factor of times the original value.
Q2 (QUANTITATIVE): If the magnitude of both charges is tripled, how does the force between them change?
Show Answer & Explanation
Answer: 9 times greater
Explanation: The force is proportional to the product of the charges (). Tripling both gives a factor of .
DEEP DIVE: RELATED CONCEPTS
An electric dipole consists of two point charges of equal magnitude but opposite sign ($+q$ and $-q$...
WHAT IS AN ELECTRIC FIELD?An electric field is a region around a charged particle where a force would be exerted on other char...
WHAT IS ELECTRIC POTENTIAL?Electric potential (or voltage) is the amount of electric potential energy per unit charge at a poin...
