What is the outcome of doubling the distance from an X-ray source, based on the inverse square law?

Doubling the distance from an X-ray source leads to a reduction in exposure rate due to the inverse square law, which states that the intensity of radiation is inversely proportional to the square of the distance from the source.

When you double the distance, the intensity of the radiation does not simply halve; instead, it decreases by a factor of four. This is computed by squaring the change in distance. Specifically, if the distance is increased from (d) to (2d), then the radiation intensity is calculated as:

[ \text{New Intensity} = \frac{\text{Original Intensity}}{(2)^2} = \frac{\text{Original Intensity}}{4} ]

Therefore, the exposure rate reduces to one quarter of the original intensity when the distance from the source is doubled, making the choice that states the exposure rate reduces to one quarter the correct answer. This understanding is crucial for maintaining safety measures in radiography as it highlights the importance of distance in radiation exposure.