Coulomb's experiment (coulomb's law)

• ViolentCorpse
In summary, Coulomb's law holds only for stationary charges. Coulomb used a torsion balance to measure the force between charged objects, which counteracted any movement of the charges. The measurement is taken after the torsion balance has reached equilibrium, ensuring that the charges are not moving and the distance between them is not changing.
ViolentCorpse
Hello,

I'm trying to imagine how Coulomb would've measured the force between electrically charged objects, but there are a few things I can't figure out.

Is it true that Coulomb's law holds only for stationary charges? If it's true, then that very stipulation of the law would be violated the moment two charges come into the electrical influence of one another, for the coulomb force would produce motion in both of them. How would we then measure the "static force" between them?

I know that Coulomb used a torsion balance so the charges probably weren't free to move. Their motion must've been counteracted by the tension in the strings they were attached to, but then I fall into another confusion: After putting a charge a known distance away from another, the force would cause the other charge (assuming that the first charge is "fixed") to displace a certain amount away or toward the first charge so the final distance between the two charges would be different than what it originally was, and likewise the force between the two at that "final" location would also be different. I can't figure out if we're measuring the force that the two would've experienced at their initial separation, or is it the force that they are experiencing at their "final" equilibrium point?

The torsion balance takes care of the movement problem, and you measure the force and distance after the torsion balance has reached equilibrium so the charge is not moving and the distance is not changing.

1 person

What is Coulomb's experiment?

Coulomb's experiment, also known as Coulomb's law, is an experiment conducted by French physicist Charles-Augustin de Coulomb in the late 1700s to study the force between electrically charged objects.

What does Coulomb's experiment demonstrate?

Coulomb's experiment demonstrates the relationship between the amount of charge on two objects, the distance between them, and the force of attraction or repulsion between the objects. It also shows that this force follows an inverse square law, meaning that it decreases as the distance between the objects increases.

How was Coulomb's experiment conducted?

Coulomb's experiment involved suspending two charged objects on a torsion balance and measuring the amount of deflection caused by the force between them. He varied the amount of charge on the objects and the distance between them to gather data and formulate his law.

What is the mathematical equation for Coulomb's law?

The mathematical equation for Coulomb's law is F = k(q1q2)/r^2, where F is the force between two charged objects, q1 and q2 are the charges on the objects, r is the distance between them, and k is a constant of proportionality.

What are the practical applications of Coulomb's law?

Coulomb's law has many practical applications in modern technology, including designing electronic devices and circuits, understanding the behavior of atoms and molecules, and predicting the behavior of particles in accelerators. It is also used in the study of astrophysics and the behavior of charged particles in space.

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