coulombs_law.py

"""
Coulombs law states that the magnitude of the electrostatic force of attraction or repulsion between two point charges
is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.

Coulomb studied the repulsive force between bodies having electrical charges of the same sign.

F = k*q1*q2/r^2

k is Coulomb's constant and equals 1/(4π*ε0).
q1 is charge of first body (C)
q2 is charge of second body (C)
r is distance between two charged bodies (m)
"""


def coulombs_law(q1: float, q2: float, radius: float) -> float:
    """
    >>> round(coulombs_law(15.5,20,15),2)
    12382849136.06
    >>> round(coulombs_law(1,15,5),2)
    5392531075.38
    >>> round(coulombs_law(20,-50,15),2)
    -39944674632.44
    >>> round(coulombs_law(-5,-8,10),2)
    3595020716.92
    >>> round(coulombs_law(50,100,50),2)
    17975103584.6
    """
    if radius <= 0:
        raise ValueError("The radius is always a positive non zero integer")
    return ((8.9875517923 * 10**9) * q1 * q2) / (radius**2)


if __name__ == "__main__":
    import doctest

    doctest.testmod(verbose=True)