Final answer:
The inverse square law can be applied to the spread of light, the force of gravity, and the force between electric charges.
Step-by-step explanation:
The inverse square law can be applied to other phenomena besides radiation. For example, it can be used to describe the decrease in illumination from a point light source as you move away from it. The energy per unit area decreases as the square of the distance from the source, following the same pattern as the inverse square law for radiation.
Moreover, the inverse square law also applies to the force of gravity. The force between two attracting masses is inversely proportional to the square of their separation. Similarly, the force between two electric charges, as described by Coulomb's law, follows an inverse-square relationship.
Therefore, the inverse square law can be applied to the spread of light, the force of gravity, and the force between electric charges.