Absorbed Dose is defined as energy absorbed per unit mass of material. Which is the SI unit?

Absorbed Dose is defined as energy absorbed per unit mass of material. Which is the SI unit?

• A. Joule per kilogram (J/kg)
• B. Roentgen (R)
• C. Gray (Gy)
• D. Rem

Answer: (C)

Absorbed dose expresses how much energy is deposited in a material per unit mass. The SI way to express that quantity is in a Gray, defined as 1 Gy = 1 joule of energy absorbed per kilogram of mass. So Gray directly represents energy per mass, making it the standard SI unit for absorbed dose. The other options don’t measure energy deposited per mass: Roentgen is exposure in air (ionizations in air), and Rem is a dose-equivalent unit that accounts for biological effect rather than raw energy deposition. Joule per kilogram is the same quantity, but Gray is the conventional SI unit used for absorbed dose.

Absorbed dose expresses how much energy is deposited in a material per unit mass. The SI way to express that quantity is in a Gray, defined as 1 Gy = 1 joule of energy absorbed per kilogram of mass. So Gray directly represents energy per mass, making it the standard SI unit for absorbed dose.

The other options don’t measure energy deposited per mass: Roentgen is exposure in air (ionizations in air), and Rem is a dose-equivalent unit that accounts for biological effect rather than raw energy deposition. Joule per kilogram is the same quantity, but Gray is the conventional SI unit used for absorbed dose.