Radiation Safety Quiz
Questions: 16 · 10 minutes
1. Which statement best compares tissue reactions with stochastic effects of ionizing radiation?
Both are guaranteed to occur after any detectable exposure
Stochastic effects have a fixed severity that rises only after a threshold
Tissue reactions occur only through radioactive contamination
Tissue reactions generally have dose thresholds, while stochastic-effect probability is treated as increasing with dose
2. A laboratory needs to determine whether removable radioactive contamination remains on a bench. Which method is most directly suited to that purpose?
Reviewing the nearest worker's personal dosimeter
Checking the room's temperature and ventilation rate
Timing how long the radioactive material was used
Taking a wipe sample and measuring it with suitable counting equipment
3. Which is appropriate practice for an assigned personal radiation dosimeter?
Wear a colleague's dosimeter when yours is unavailable
Leave it beside the source so it records the area's maximum dose
Wear and store it as directed, and never share it with another worker
Store it with radioactive materials between shifts to test sensitivity
4. An intact sealed source passes its leak test and remains inside its undamaged housing. Which statement is most accurate?
It cannot expose anyone because sealed sources emit no radiation
It may create an external radiation field, while contamination is unlikely if the source remains sealed
It necessarily contaminates every surface in the room
It is harmless unless it is swallowed
5. A small point-like gamma source produces a dose rate of 80 units per hour at 1 metre. Ignoring scatter, approximately what would the rate be at 2 metres?
80 units per hour
40 units per hour
20 units per hour
10 units per hour
6. After handling radioactive powder, a worker finds radioactive material on one glove. Which statement best describes the situation?
The glove is contaminated because radioactive material is present on it
The worker has received external exposure, but contamination is impossible
The glove has become a sealed radiation source
The reading represents background radiation because it is on protective clothing
7. A task near a radiation source normally takes 12 minutes. Without changing distance or shielding, which change most directly reduces the worker's dose?
Dividing the task among more written procedures
Practising beforehand so the task can be completed correctly in less time
Completing the same task more slowly to avoid mistakes
Wearing two personal dosimeters instead of one
8. A radionuclide has a physical half-life of 8 days. If no material is added or removed, what fraction of the original activity remains after 24 days?
One-half
One-quarter
One-sixteenth
One-eighth
9. Which set lists common routes by which radioactive material can enter the body?
Inhalation, ingestion, and entry through a wound
External irradiation, sound transmission, and skin temperature
Distance, shielding, and exposure time
Reflection, refraction, and diffraction
10. A standard diagnostic X-ray unit has completed an exposure and has been switched off. Which statement is generally correct?
It continues emitting X-rays until the room is ventilated
It remains radioactive for one physical half-life
It does not continue producing an X-ray beam after power generation stops
It becomes a permanently sealed radioactive source
11. In radiation protection, what does ALARA mean?
Avoid all work involving ionizing radiation whenever alternatives exist
Keep every measured dose below the instrument's detection limit
Keep exposure as low as reasonably achievable, considering practical controls
Allow radiation work only when no shielding is required
12. A sealed source cannot be found in its expected storage location. What is the most appropriate immediate response?
Continue normal work until the source appears during routine cleaning
Restrict access if safe, avoid unplanned searching or handling, and notify the radiation safety contact immediately
Ask an untrained colleague to search nearby bins by hand
Move radiation warning signs elsewhere so staff do not become alarmed
13. Which material is commonly useful for attenuating penetrating X-rays or gamma rays?
A sheet of paper
A thin cotton layer
An open air gap of a few millimetres
A suitably designed thickness of lead or concrete
14. What does the standard radiation trefoil symbol indicate?
A potential ionizing-radiation hazard or controlled radiation-related area is present
Protective clothing guarantees that exposure cannot occur
Only non-ionizing radiation equipment is present
The area is contaminated at a medically dangerous level
15. Which statement correctly distinguishes the gray (Gy) from the sievert (Sv)?
The gray measures only contamination, while the sievert measures exposure time
The gray expresses absorbed dose, while the sievert is used for equivalent or effective dose reflecting biological weighting
The gray is used only for X-rays, while the sievert is used only for gamma rays
The units are interchangeable names for radioactive decay rate
16. For a high-energy beta source, which material is generally preferred as the first shielding layer to limit bremsstrahlung production?
A low-atomic-number material such as acrylic
Thin paper only
Dense steel only
Lead only