Final answer:
The intensity of electromagnetic waves in empty space with no absorption or interference effects is inversely proportional to the distance from the source squared.
Step-by-step explanation:
The intensity of electromagnetic waves in empty space with no absorption or interference effects is inversely proportional to the distance from the source squared (I ∝ 1/r²). This means that as the distance from the source increases, the intensity of the waves decreases quadratically.