Which unit is mentioned as a dose unit in the context of occupational exposure?

• A. rem
• B. sievert
• C. gray
• D. becquerel

Answer: (A)

In occupational exposure, the important quantity is dose equivalent, which accounts for the type of radiation and the sensitivity of tissues to produce a biological effect. The rem has traditionally been used to express this dose equivalent in many occupational settings, and it remains familiar in exam contexts. The SI counterpart is the sievert, with 1 sievert equal to 100 rem, so both describe the same concept in different unit systems. The gray measures absorbed dose—energy deposited per unit mass—without weighting for radiation type, so it isn’t the dose equivalent used for occupational exposure. The becquerel measures activity (decays per second) of a source, not the dose absorbed by tissue. Thus, rem is the unit specifically associated with dose equivalent in occupational exposure.