What unit is used to describe ionization in air?

• A. Röntgen
• B. Gray
• C. Roentgen/Gya
• D. Rad

Answer: (C)

The correct unit used to describe ionization in air is the Röntgen, which is a measure of exposure to ionizing radiation. This unit specifically quantifies the amount of ionization produced in air by X-rays or gamma rays. One Röntgen is defined as the amount of radiation that will produce a certain amount of ion pairs in a specified volume of air.

The term "Roentgen/Gya" is indeed sometimes used interchangeably, particularly in contexts where comparisons are made between different measurement systems. "Gya" refers to the Gray, which is a unit of absorbed dose, and not directly related to ionization in air. Therefore, although "Roentgen/Gya" may be included in the answer, the critical component relevant to ionization in air specifically aligns with the Röntgen.

In summary, the Röntgen is directly associated with measuring ionization in air, making it the appropriate choice.