Review of Radioactivity

Question 1

The rate of decay of a radioactive material is called

Answer 1

Activity.

Question 2

The SI unit of activity is the

Answer 2

Becquerel (Bq).

Question 3

1 Bq =

Answer 3

1 decay/second

Question 4

Another unit of activity is the

Answer 4

Curie (Ci)

Question 5

1 Ci =

Answer 5

37 billion Bq

Question 6

The equation for radioactive decay is

Answer 6

A = A₀ e^-λ​t

Question 7

The mean life of a radioative material is

Answer 7

τ = 1/λ = 1.44 T_1/2

Question 8

The half-life T_1/2 =

Answer 8

ln(2)/λ

Question 9

The total number of radioactive atoms in a sample is

Answer 9

N₀ = A₀ τ

Question 10

Gamma rays originate from

Answer 10

nuclear reactions or from proto-electron annihilation.

Question 11

Beta particles are

Answer 11

electrons or positrons.

Question 12

Alpha particles are

Answer 12

Helium Atoms: ⁴ ₂He

Question 13

Half-life is defined as

Answer 13

the amount of time it takes for half of the original samples to decay.

Question 14

Mean-life is

Answer 14

the amount of time it will take for a sample to completely decay if the initial activity were to remain constant.

Question 15

Exposure (X) is

Answer 15

the ability of of a photon beam to ionize air.

Question 16

Exposure can also be understood as

Answer 16

Charqe Q produced by photon beam interaction with mass m.

Question 17

[X] =

Answer 17

Roentgen or C/kg

Question 18

KERMA:

Answer 18

Kinetic Energy Released per unit Mass at a specific point

Question 19

Kerma = K =

Answer 19

E_Tr /m,

where E_Tr is the sum of all the initial K-energy of all charged particles liberated by an uncharged ionizing particles in a material of mass m.

Question 20

Exposure = X =

Answer 20

Q/m,

charge over mass.

Question 21

The unit of KERMA (K) is

Answer 21

J/kg or Gray