Coulomb's Law

(Carrie MacLeod)
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Charles Augustin de Coulomb published this law in the late 18th century. It was derived from observations he made while experimenting with a Torsion Balance. During his experiments, Coulomb discovered that the electric force is directly proportional to the charges and inversely proportional to the distance between the centers of each object.

Coulomb’s law is used to solve for the force exerted by one charged object onto another. This force can either be attraction, between a positive and a negative charge, or repulsion, between two like charges.

Coulombs constant, k, is a proportionality constant that takes into account the properties of space. For more information on the derivation of k view the link below. However, all that is needed for physics 30 is to know that k=8.99x10^9 Nm2/C2.

external image Electr4.gif
Fe = Force (N)
q = Charge (C)
r = distance between the centers of the charged objects (m)
k = 8.99x10^9 Nm2/C2