Experiments with electric charges have shown that if two objects each have an electric charge, they exert an electric force on each other. The magnitude of the force is linearly proportional to the net charge on each object and inversely proportional to the square of the distance between them. The direction of the force vector is along the imaginary line joining the two objects and is dictated by the signs of the charges involved.

Newton's third law applies to the Coulomb force — the force on each charge is equal in magnitude and opposite in direction to the force experienced by the other.

Interestingly, the Coulomb force does not depend on the mass of the objects. It is quantitatively similar to the gravitational force, the difference being that the latter is always attractive.

It is important to note that the electric force is not constant; it is a function of the separation distance between the two charges. If either the test charge or the source charge (or both) move, the separating distance changes; hence, the force changes. An immediate consequence is that the direct application of Newton’s laws with this force can be mathematically tricky. It can usually be done, but more straightforward methods of calculating whatever physical quantity we are interested in are preferred.

The new constant in Coulomb's law is called the permittivity of free space or the permittivity of vacuum. It has a significant physical meaning, related to the speed of light in vacuum.

Tags
Coulomb s LawElectric ChargeElectric ForceMagnitudeDistanceForce VectorNewton s Third LawGravitational ForcePermittivity Of Free SpaceSeparation DistanceTest ChargeSource Charge

Dal capitolo 22:

article

Now Playing

22.5 : Coulomb's Law

Electric Charges and Fields

8.1K Visualizzazioni

article

22.1 : Cariche elettriche

Electric Charges and Fields

16.8K Visualizzazioni

article

22.2 : Fonti e proprietà della carica elettrica

Electric Charges and Fields

9.1K Visualizzazioni

article

22.3 : Conduttori e isolanti

Electric Charges and Fields

7.7K Visualizzazioni

article

22.4 : Conduttori di carica per induzione

Electric Charges and Fields

7.2K Visualizzazioni

article

22.6 : La legge di Coulomb e il principio di sovrapposizione

Electric Charges and Fields

8.1K Visualizzazioni

article

22.7 : Confronto tra forze elettriche e gravitazionali

Electric Charges and Fields

2.3K Visualizzazioni

article

22.8 : Campo elettrico

Electric Charges and Fields

9.8K Visualizzazioni

article

22.9 : Campo elettrico di due cariche uguali e opposte

Electric Charges and Fields

5.4K Visualizzazioni

article

22.10 : Distribuzioni di carica continua

Electric Charges and Fields

6.5K Visualizzazioni

article

22.11 : Campo elettrico di una carica in linea continua

Electric Charges and Fields

1.3K Visualizzazioni

article

22.12 : Campo elettrico di un disco carico

Electric Charges and Fields

1.8K Visualizzazioni

article

22.13 : Linee di campo elettrico

Electric Charges and Fields

6.8K Visualizzazioni

article

22.14 : Proprietà delle linee di campo elettrico

Electric Charges and Fields

7.2K Visualizzazioni

article

22.15 : Dipoli elettrici e momento di dipolo

Electric Charges and Fields

4.7K Visualizzazioni

See More

JoVE Logo

Riservatezza

Condizioni di utilizzo

Politiche

Ricerca

Didattica

CHI SIAMO

Copyright © 2025 MyJoVE Corporation. Tutti i diritti riservati