Dose in rad/Gy absorbed per unit time is described as what?

• A. Dose rate
• B. Dose
• C. Exposure
• D. Dose equivalent

Answer: (A)

The concept being tested is dose rate: the amount of energy deposited in tissue per unit mass per unit time. Absorbed dose tells you how much energy is deposited overall (measured in Gy or rad). When you divide that absorbed dose by the time over which the energy is deposited, you get the dose rate (for example, Gy per second or rad per second). This helps describe how quickly radiation is delivered during an exposure.

Why this is the best fit: the phrase “absorbed per unit time” requires a rate, not the total amount. Dose rate specifically captures that timing aspect, whereas dose alone is the total energy per mass, without reference to time.

To contrast briefly: exposure refers to ionization produced in air (in units related to air kerma), not the energy absorbed in tissue. Dose is the total energy absorbed, without time. Dose equivalent adds weighting to reflect biological effect, giving a risk-oriented measure in Sv.