Under the inverse square relationship, what happens to radiation exposure as distance from the source increases?

Under the inverse square relationship, what happens to radiation exposure as distance from the source increases?

• A. It increases
• B. It decreases
• C. It remains the same
• D. It depends on the source

Answer: (B)

Exposure follows the inverse square law: as you move away from the source, the radiation that reaches a given area drops with the square of the distance. The energy spreads over a larger spherical surface, so intensity is proportional to 1/r^2. That means increasing distance reduces exposure—doubling distance gives one quarter of the exposure, tripling distance gives one ninth, and so on. This describes the general trend for a point source in open space; real sources can introduce other factors, but the basic relationship is a decrease with distance.

Exposure follows the inverse square law: as you move away from the source, the radiation that reaches a given area drops with the square of the distance. The energy spreads over a larger spherical surface, so intensity is proportional to 1/r^2. That means increasing distance reduces exposure—doubling distance gives one quarter of the exposure, tripling distance gives one ninth, and so on. This describes the general trend for a point source in open space; real sources can introduce other factors, but the basic relationship is a decrease with distance.