Chapter 1
The physics and chemistry of radiation absorption

1. What is the difference between X-rays and gamma rays?

a. X-rays are produced extranuclearly whereas gamma rays are produced in nuclear decays.

b. X-rays have higher energies than gamma rays.

c. gamma rays are produced by bremsstrahlung.

d. X-rays and gamma rays interact with matter differently.

2. What is the main source of natural background radiation?

a. Electrons.

b. X-rays.

c. Neutrons.

d. Alpha-particles.

3. Which photon processes are dominant in the context of diagnostic radiology?

a. Compton scattering and photoelectric effect.

b. Photoelectric effect and pair production.

c. Compton scattering and pair production.

d. Compton and Rayleigh scattering.

4. The mass absorption coefficient for Compton scattering is independent of the atomic number (Z) of the absorber whereas the mass absorption coefficient for photoelectric effect depends strongly on Z.

a. True.

b. False.

5. Direct action of radiation is the dominant process for:

a. X-rays.

b. Neutrons and alpha particles.

c. Electrons.

d. Gamma rays.

6. Which of the following statements is true?

a. Indirect action can be modified by protectors or sensitizers.

b. Direct action can be modified by protectors or sensitizers.

7. A free radical is:

a. Any charged particle.

b. An atom or molecule with an unpaired electron in the outer shell.

c. An atom with an even number of electrons.

d. A chemically stable atom.

8. The main interaction process(es) of neutrons in biologic matter are:

a. Magnetic scattering.

b. Coulomb scattering by orbital electrons.

c. Fission.

d. Elastic and inelastic scattering by nuclei.

9. All types of radiation can induce biologic effects by direct or indirect action.

a. True.

b. False.

10. What is the main reason for the difference in biologic effects caused by neutrons and photons?

a. The energy of the radiation.

b. The fact that the charged particles produced by neutrons are, for the most part, positively charged.

c. The density of ionization.

d. The fact that neutrons can interact with nuclei.

[Main Page]