In Coulomb's law, C represents the coulomb, which is the SI unit of electric charge.
Understanding the Coulomb
The coulomb (C) is the standard unit for measuring electric charge. It's defined as the amount of charge transported by a current of one ampere in one second.
- Definition: 1 Coulomb (C) = 1 Ampere (A) * 1 Second (s)
Coulomb's Law and the Role of Charge
Coulomb's law mathematically describes the electrostatic force between two charged objects. The law states:
F = k (|q1 q2|) / r²
Where:
- F is the electrostatic force
- k is Coulomb's constant (approximately 8.9875 × 109 N⋅m²/C²)
- q1 and q2 are the magnitudes of the charges, measured in coulombs (C)
- r is the distance between the charges
In this formula, the magnitude of the charges, q1 and q2, are expressed in coulombs. The larger the values of q1 and/or q2, the greater the electrostatic force between the two charges.
Example
Imagine two small spheres, one with a charge of +2C and another with a charge of -3C, separated by a distance of 1 meter. Using Coulomb's Law, we can calculate the electrostatic force between them:
F = (8.9875 × 109 N⋅m²/C²) (|2 C -3 C|) / (1 m)²
F = (8.9875 × 109 N⋅m²/C²) * (6 C²) / (1 m)²
F = 5.39 x 1010 N
The force would be attractive because the charges are opposite, and its magnitude is approximately 5.39 x 1010 Newtons.
