How is the intensity of electromagnetic radiation related to distance?

How is the intensity of electromagnetic radiation related to distance?

• A. Directly proportional to the distance
• B. Inversely related to the distance
• C. Inversely related to the square of the distance
• D. Constant regardless of distance

Answer: (C)

The intensity of electromagnetic radiation is described by the inverse square law, which indicates that intensity is inversely related to the square of the distance from the source. This means that as you move away from the source of the radiation, the intensity decreases rapidly; specifically, if you double the distance from the source, the intensity becomes one-fourth of what it was at the original distance.

This relationship arises because electromagnetic radiation spreads out over a larger area as it moves away from the source, leading to a decrease in energy concentration per unit area. As a result, understanding this principle is crucial for fields such as radiography, hygiene in equipment settings, and radiation safety, as it directly impacts exposure and image quality.