NRRPT Physics and Interactions 3

Question 1

Bremsstrahlung radiation efficiency increases with:

Accepted Answer

Higher atomic number (Z) of the target and higher electron energy

Answer

Bremsstrahlung production is proportional to Z² and to the electron kinetic energy, so high-Z targets (like tungsten) and high-energy electrons maximize bremsstrahlung yield.

Question 2

The mass attenuation coefficient (μ/ρ) of a compound material can be calculated using:

Accepted Answer

The mixture rule: sum of weight-fraction-weighted elemental coefficients

Answer

The mixture rule states that μ/ρ for a compound equals the sum of each element's weight fraction multiplied by its elemental mass attenuation coefficient.

Question 3

Which quantity is conserved in all nuclear reactions?

Accepted Answer

Total baryon number and charge

Answer

Conservation laws in nuclear reactions require that total baryon number (A) and electric charge (Z) are conserved, along with energy and momentum.

Question 4

Positron annihilation produces two photons, each with an energy of:

Accepted Answer

0.511 MeV traveling in opposite directions

Answer

When a positron annihilates with an electron, two 0.511 MeV photons are emitted in opposite directions (180° apart) to conserve momentum.

Question 5

The range of alpha particles in tissue is approximately:

Accepted Answer

A few tens of micrometers to ~100 μm

Answer

Alpha particles (4–8 MeV) have very short ranges in tissue, typically a few tens to about 100 micrometers, due to their large charge and mass causing dense ionization.

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

NRRPT Physics and Interactions 3