RSO Radiation Physics and Fundamentals 2

Question 1

The traditional unit of radioactivity is the Curie (Ci). One Curie is defined as:

Accepted Answer

3.7 × 10^10 disintegrations per second

Answer

1 disintegration per second

Answer

3.7 × 10^6 disintegrations per minute

Answer

1 joule of energy absorbed per kilogram

Question 2

In electron capture decay, the nucleus captures an orbital electron and emits:

Accepted Answer

A neutrino and characteristic X-rays

Answer

A gamma ray only

Answer

A positron and a neutrino

Answer

An alpha particle

Question 3

The specific activity of a radioactive material is defined as:

Accepted Answer

Activity per unit mass

Answer

Activity per unit volume

Answer

Activity per unit time

Answer

Activity per unit area

Question 4

Which of the following radionuclides is a pure beta emitter with no associated gamma radiation?

Accepted Answer

H-3 (Tritium)

Answer

Co-60

Answer

Cs-137

Answer

I-131

Question 5

The mean free path of a photon in a material is best described as:

Accepted Answer

The average distance a photon travels before interacting

Answer

The distance at which intensity drops to 50% of the original

Answer

The thickness of shielding required to stop all photons

Answer

The distance at which dose rate equals the background level

Question 6

If a radionuclide has a physical half-life of 6 hours and a biological half-life of 12 hours, what is its effective half-life in the body?

Accepted Answer

4 hours

Answer

18 hours

Answer

9 hours

Answer

6 hours

Question 7

Secular equilibrium between a parent and daughter radionuclide occurs when:

Accepted Answer

The parent's half-life is much longer than the daughter's

Answer

Parent and daughter have equal half-lives

Answer

The daughter's half-life is much longer than the parent's

Answer

The activity of the parent equals zero