Answer: This law allows us to know how the illuminance of the star varies with the square of the distance.
Step-by-step explanation:
The Law of the Inverse of the Square for light, allows us to determine, in the case of a star, and considering it as a point source, how its illuminance
(power per unit area) varies with the square of the distance
that separates us from it when measuring its apparent brightness.
This law is expressed as follows:
Where
is the pointance (The flux power per unit solid angle, which is somehow analog with the intensity).
As we can see, as the distance from the light source increases, the illuminance decreases.