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1. Inverse Square Law

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   The Inverse-Square Law is a fundamental principle describing how the intensity of a physical quantity, such as radiation, gravity, or electrostatic force, diminishes as the distance from the source of that quantity increases. Mathematically, the intensity ($\text{I}$) is inversely proportional to the square of the distance ($r$) from the point source:
   $$\text{I} \propto \frac{1}{r^2}$$

2. Inverse Square Law

   Linked via "point source"

   Illumination and Radiant Flux
   For a point source emitting energy (such as light or sound waves) uniformly in all directions, the intensity ($\text{I}$) of the observed flux decreases as the square of the distance. If $\text{L}$ is the source luminosity (power output), then:
   $$\text{I} = \frac{\text{L}}{4\pi r^2}$$