How many ergs of air represent one roentgen?

One roentgen is defined as a unit of exposure to ionizing radiation that produces a specific amount of ionization in air. The relationship to ergs is established through the concept of energy deposited in a volume of air due to radiation exposure. Specifically, one roentgen of exposure is equal to approximately 87 ergs of energy deposited in air. Therefore, the selection of approximately 86 ergs as the answer is aligned with the recognized conversion, making it the correct choice.

This information is crucial in the context of environmental health, where understanding radiation exposure and its effects is essential for ensuring public safety and implementing appropriate health policies. The knowledge of these units and their conversions aids professionals in assessing environmental hazards accurately.