The Gray (Gy) is equal to which unit?

The Gray (Gy) is equal to which unit?

• A. Coulombs/kilogram (C/kg)
• B. Exposure
• C. Joules/kilogram (J/kg)
• D. Coulombs/hour (C/hour)

Answer: (C)

The Gray measures absorbed dose—the energy deposited in a mass of material per unit mass. By definition, 1 Gray equals 1 joule of energy absorbed per kilogram of matter. So the Gray is the same as joules per kilogram. Coulombs per kilogram represents exposure in terms of charge produced per mass (ionization in air), not energy deposited in the tissue. Coulombs per hour is just a rate of charge flow, which isn’t related to dose.

The Gray measures absorbed dose—the energy deposited in a mass of material per unit mass. By definition, 1 Gray equals 1 joule of energy absorbed per kilogram of matter. So the Gray is the same as joules per kilogram.

Coulombs per kilogram represents exposure in terms of charge produced per mass (ionization in air), not energy deposited in the tissue. Coulombs per hour is just a rate of charge flow, which isn’t related to dose.