NRRPT Radiation Fundamentals & Detection 5

Question 1

A rem is related to a rad by which formula?

Accepted Answer

Both A and C are correct expressions

Answer

Dose equivalent (rem) = absorbed dose (rad) × quality factor Q; in SI, effective dose (Sv) = absorbed dose (Gy) × radiation weighting factor WR — both express the same biological weighting concept.

Question 2

What phenomenon causes the 'wall effect' artifact in ionization chamber measurements of photon beams?

Accepted Answer

Secondary electrons generated in chamber walls contributing to ionization

Answer

Energetic secondary electrons ejected from the chamber wall can travel into the gas volume and produce additional ionization, affecting measurement accuracy.

Question 3

In nuclear stability, which statement about the neutron-to-proton (N/Z) ratio is correct?

Accepted Answer

The stable N/Z ratio increases above 1.0 for heavier nuclei

Answer

Heavy stable nuclei require more neutrons than protons to overcome increasing Coulomb repulsion; the stable N/Z ratio rises above 1 for Z > 20.

Question 4

Coherent (Rayleigh) scattering differs from Compton scattering in that it:

Accepted Answer

Scatters the photon with essentially no energy loss

Answer

In Rayleigh scattering, the photon interacts with the atom as a whole and is deflected with negligible energy loss, unlike Compton which involves energy transfer to a free electron.

Question 5

Which statement correctly describes the operation of a silicon semiconductor detector?

Accepted Answer

Ionizing radiation creates electron-hole pairs that are swept to electrodes by an applied bias

Answer

In silicon detectors, radiation creates electron-hole pairs; reverse bias voltage sweeps carriers to respective electrodes, producing a charge pulse proportional to deposited energy.

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

NRRPT Radiation Fundamentals & Detection 5