Final answer:
Absorbed dose is a scalar quantity that measures the energy deposited by radiation in a unit mass, commonly measured in grays (Gy) or rads.
Step-by-step explanation:
The absorbed dose from ionizing radiation is a measure of the energy deposited by the radiation in a unit mass of matter. It is a scalar quantity, because it has magnitude — the amount of energy absorbed per unit mass — but does not have a specific direction in space. The common units used to express absorbed dose are the gray (Gy) and the rad, where 1 Gy is equivalent to 100 rads. The definition of absorbed dose is gray (Gy), which is the absorption of one joule of radiation energy per kilogram of matter (J/kg), and for the rad, the absorption is 0.01 J/kg.