What is the formula for the inverse square law?

The inverse square law is a fundamental principle in physics, particularly in the fields of light, gravity, and electromagnetic radiation. It states that the intensity of a physical quantity (such as light or gravitational force) is inversely proportional to the square of the distance from the source of that quantity.

The formula that correctly represents this relationship is given as the ratio of intensities being equal to the square of the distances. By stating I1/I2 = D2^2/D1^2, it describes how if you increase the distance D2 from the source compared to distance D1, the intensity I1 will decrease in proportion to the square of that distance factor. This captures the essence of the inverse relationship; as the distance from the source increases, the intensity diminishes rapidly, following the square of the distance change.

The formula effectively illustrates the point that doubling the distance results in a decrease of the intensity to one-fourth of its original value, demonstrating the significant impact distance has on intensity as per the inverse square law.