Physics of Radiation l Oral radiology MCQs 4th year for dental students

More MCQ on Physics of Radiation in Oral radiology

1. Examples of electromagnetic radiation include all EXCEPT one. Which one is the EXCEPTION?

a. Visible light.

b. Radio waves.

c. MR imaging.

d. Beta particles.

2. Bundles of energy are called

a. photons.

b. radioactive.

c. wave theory.

d. electron volts.

3. The amount of energy acquired by one electron accelerating through a potential difference of 1 volt is called the

a. electron volt.

b. linear energy transfer.

c. radioactivity potential.

d. wavelength to energy relationship.

4. Which is a property of electromagnetic waves?

a. Cause ionization.

b. Have mass and weight.

c. Travel at the velocity of light in a vacuum.

d. Do not cause biologic changes in living cells.

5. Which unit is typically used to characterize low energy photons such as radio waves?

a. Energy. 

b. Direction.

c. Frequency. 

d. Wavelengths.

6. Which are the primary components of an x-ray machine?

a. Cathode and anode.

b. Tube head and filters.

c. Control panel and collimator.

d. X-ray tube and power supply.

7. Which component of the x-ray machine is necessary in order to generate and accelerate electrons?

a. Focal spot.

b. Power supply.

c. Tube vacuum.

d. Focusing cup.

8. Which is the source of electrons within the x-ray tube?

a. Anode.

b. Filament.

c. Control panel.

d. Focusing cup.

9. The number of electrons emitted is determined by the

a. thermal conductor.

b. high-voltage source.

c. temperature of the filament.

d. material composing the filament.

10. The focusing cup is made of

a. copper.

b. granite.

c. tungsten.

d. molybdenum.

11. Which is the purpose of the target in an x-ray tube?

a. Remove generated heat.

b. Stop production of electrons.

c. Convert electrons into x-ray photons.

d. Aim the electrons toward the area to be imaged.

12. All are characteristics of ideal target material EXCEPT one. Which one is the EXCEPTION?

a. High melting point.

b. High vapor pressure.

c. High atomic number.

d. High thermal conductivity.

13. Copper and which other component of the x-ray machine tube head dissipates heat?

a. Insulating oil.

b. Metal housing.

c. Glass envelope.

d. Electronic focusing cup.

14. Which is the purpose of a rotating anode?

a. Increase production of x-rays.

b. Decrease number of electrons.

c. Eliminate need for angled target.

d. Dissipate heat from small focal spot.

15. Which type of x-ray machine utilizes a stationary anode?

a. Intraoral.

b. Tomographic.

c. Cephalometric.

d. Medical computed tomography.

16. The flow of electrons from the cathode filament, across the tube to the anode, and then back to the filament is called the

a. voltage.

b. tube current.

c. x-ray production.

d. filament transformer.

17. Which x-ray machine control regulates the filament temperature?

a. On/off switch.

b. Exposure time.

c. Milliamperage (mA).

d. Kilovolt peak (kVp).

18. Which x-ray machine control converts the primary voltage from the input source into the desired secondary voltage?

a. On/off switch.

b. Exposure time.

c. Milliamperage (mA).

d. Kilovolt peak (kVp).

19. Which is an advantage of a constant-potential xray machine over a self-rectifying x-ray machine, given a voltage and radiographic density setting?

a. Lower patient radiation dose.

b. Increased radiation production.

c. More efficient use of electricity.

d. Effective use of inverse voltage.

20. Which x-ray machine control limits the duration of x-ray production?

a. On/off switch.

b. Exposure time.

c. Milliamperage (mA).

d. Kilovolt peak (kVp).

21. How many impulses of radiation equivalent occur in a one-fourth (14) second exposure?

a. 9.

b. 15.

c. 20.

d. 30.

22. Which is the approximate heat storage capacity for anodes in dental x-ray tubes?

a. 5 kHU.

b. 15 kHU.

c. 20 kHU.

d. 30 kHU.

23. Which factor determines the interval between successive x-ray exposures?

a. kVp.

b. Exposure time.

c. Heat dissipation.

d. Number of electrons.

24. Which is the primary form of radiation produced from an intraoral x-ray tube?

a. Particulate.

b. Secondary.

c. Characteristic.

d. Bremsstrahlung.

25. When an electron from the filament directly hits the nucleus of a target atom, which entity is produced?

a. New atom.

b. Single x-ray photon.

c. Decelerated electron.

d. Characteristic radiation.

26. Which statement does NOT explain the continuous spectrum of x-ray photons?

a. Accelerated electrons form characteristic radiation.

b. Deflected electrons give up varying amounts of energy.

c. Electrons striking the target have varying levels of kinetic energy.

d. Electrons participate in many bremsstrahlung interactions before losing all their kinetic energy.

27. Which occurs when an electron is ejected from its orbital by an incident electron?

a. Particulate radiation.

b. Secondary radiation.

c. Characteristic radiation.

d. Bremsstrahlung radiation.