ASNT Industrial Radiography Radiation Safety Practice Test

How many milliroentgens are equivalent to one roentgen (1R)?

1. 100 milliroentgen

2. 1000 milliroentgen

3. 10,000 milliroentgen

4. 100,000 milliroentgen

The correct answer is: 1000 milliroentgen

One roentgen (1R) is equivalent to 1000 milliroentgens. This is based on the definition of the roentgen as a unit of measurement for exposure to ionizing radiation, specifically in terms of the amount of X-ray or gamma radiation needed to produce a specific amount of ionization in air. Since the prefix "milli-" denotes one-thousandth of a unit, converting roentgens to milliroentgens involves multiplying by 1000. Thus, it's essential to understand that a roentgen represents a larger unit of radiation exposure, and knowing this conversion is fundamental in radiation safety practices, including industrial radiography.