What is light intensity inversely proportional to?

Light intensity is inversely proportional to the square of the distance from the source of light. This concept comes from the inverse square law, which states that as light travels away from its source, the intensity of the light decreases with the square of the distance.

In practical terms, if you double the distance from a light source, the intensity of light that reaches a surface at that distance becomes one-fourth of the original intensity. This is because the same amount of light is spread over a larger area as the distance increases, leading to a decrease in intensity.

This principle is crucial for understanding various applications, including photography, plant growth, and even the behavior of stars in astronomy, where the brightness we perceive diminishes significantly with distance due to the surface area over which the light is spread.