Inverse Square Law
E from1 = k q1 / r122 for a point charge, and
g = G M / r2 for a mass. Why do both have an inverse square of distance (1/r2) ?
If we consider that the field consists of a bunch of “moving particles” that make up the field, the density of particles, and hence the strength of the field, will decrease as they spread out over a larger area (A=4pr2).
[The 4p is incorporated into the constants k and G.]