Power is defined as energy per time unit, while intensity is defined as power per area unit. Both power and intensity depend on constants like pi and variables like the radius of the object, with intensity inversely proportional to the square of the radius due to the inverse square law. The inverse square law states that intensity spreads over an increasing surface area proportional to the square of the distance from the point source. In a sample problem, a diver closer to a exploding canon would hear it at a higher intensity and first compared to a person further on a boat, due to the inverse relationship between intensity and distance as defined by the inverse square law.