DENTAL RADIOLOGY FINAL EXAM LATEST 2024 WITH 100%
CORRECT VERIFIED ANSWERS. GRADED A+
1. If you increase distance, what happens to the intensity of the beam?: The
intensity decreases so increase exposure time by four
2. If you decrease distance, what happens to the intensity of the beam?: The
intensity increases so decrease exposure time by four
3. What does kVp stand for?: Kilovoltage potential
4. What type of contrast is black and white?: high contrast (short scale)
5. What type of contrast has many shades of gray; a lot of detail?: Low contrast
(long scale)
6. increase kVp=: decrease in contrast
7. decrease kVp=: increase in contrast
8. What is the inverse square law?: Increased TFD increases intensity, therefore
increase distance decreases density so multiply exposure time by 4. Increase TFD
and increase exposure time to get same exposure time.
9. How much greater is intensity at a short distance?: 4x's as greater; intensity is 1/4
as intense at 16"
10. What is the half value layer?: Measurement of quality of beam outside the
tubehead; measures accuracy of kVp setting; aluminum filter. Word quality has to be
there.
11. Quality=: kVp
12. What does kVp control?: wavelength
13. Explain how x-rays are produced in bursts of radiation instead of a steady
stream.: Self-rectifying circuitry results in on/off polarity which creates bursts of
radiation.
14. Explain why the primary beam of radiation is polychromatic.: Because the
electrons do not all brake at the focal spot, long wave & short-wave radiation is
produced. Self-rectification plays a part bc of the peaking of the kVp circuitry.
15. What is the purpose of an intensifying screen?: Decreases patient exposure to
radiation
16. Which screen is better, green or blue?: Green, 4x's faster than blue.
17. Breamstrahlung radiation: Breaking of radiation
18. Why is the long cone paralleling technique the preferred technique to be used in
exposing radiographs?: Fewer retakes, less entry and exit doses to critical organs,
less tissue volume exposed
1/8
, .
19. What effect does OFD have on a radiograph?: increase OFD causes
magnification, XCP biteblock causes magnification so increase TFD to decrease
magnification
20. What is the Compton Effect?: Outer orbiting electrion, -ion and +ion, only uses
part of its energy; scatter
21. What is the Photoelectric effect?: Inner orbiting electron, -ion and +ion,
uses all of its energy; no scatter.
22. Explain the role of the kVp circuit in the production of X-rays.: kVp controls
speed of electrons from the cathode to the anode
23. How does wavelength effect frequency?: The shorter the wavelength, the higher
the frequency; the longer the wavelength, the lower the frequency.
24. Explain the purpose of the silver halide crystals.: They store radiant energy in an
invisible pattern until processed; size of crystals determines film speed, larger the
crystals the faster the film speed.
25. What error has been made when the film looks clear?: No exposure to radiation
26. What error has been made when the image is darker with an extra set of teeth?:
Double exposure
27. What error has been made when the film is lighter with a visible geometric
pattern?: Film packet was reversed
28. A 0.5 second exposure would produce how many impulses of x-radiation?-
: 30 imp. (60 imp in one second so .5x60=30)
29. The teeth on an x-ray appear stretched out over the film. This was not a result
of bending the film. What caused this and how would it be corrected?:
Elongation caused by too little VA. Correct elongation by increasing VA.
30. How to correct foreshortening: Decrease VA
31. What TFD would produce a radiograph with the least image magnification?
A. 4 in B. 7 in
8 in
16 in: D. 16 in
32. Which term describes the white areas on the processed radiograph?:
Radiopaque
33. Which term best describes an x-ray beam that is composed of a variety of
wavelengths?: Polychromatic
34. Based on the inverse square law, what happens to the intensity of the x-ray
beam when the TFD is doubled?: Intensity is one quarter as great
2/8
CORRECT VERIFIED ANSWERS. GRADED A+
1. If you increase distance, what happens to the intensity of the beam?: The
intensity decreases so increase exposure time by four
2. If you decrease distance, what happens to the intensity of the beam?: The
intensity increases so decrease exposure time by four
3. What does kVp stand for?: Kilovoltage potential
4. What type of contrast is black and white?: high contrast (short scale)
5. What type of contrast has many shades of gray; a lot of detail?: Low contrast
(long scale)
6. increase kVp=: decrease in contrast
7. decrease kVp=: increase in contrast
8. What is the inverse square law?: Increased TFD increases intensity, therefore
increase distance decreases density so multiply exposure time by 4. Increase TFD
and increase exposure time to get same exposure time.
9. How much greater is intensity at a short distance?: 4x's as greater; intensity is 1/4
as intense at 16"
10. What is the half value layer?: Measurement of quality of beam outside the
tubehead; measures accuracy of kVp setting; aluminum filter. Word quality has to be
there.
11. Quality=: kVp
12. What does kVp control?: wavelength
13. Explain how x-rays are produced in bursts of radiation instead of a steady
stream.: Self-rectifying circuitry results in on/off polarity which creates bursts of
radiation.
14. Explain why the primary beam of radiation is polychromatic.: Because the
electrons do not all brake at the focal spot, long wave & short-wave radiation is
produced. Self-rectification plays a part bc of the peaking of the kVp circuitry.
15. What is the purpose of an intensifying screen?: Decreases patient exposure to
radiation
16. Which screen is better, green or blue?: Green, 4x's faster than blue.
17. Breamstrahlung radiation: Breaking of radiation
18. Why is the long cone paralleling technique the preferred technique to be used in
exposing radiographs?: Fewer retakes, less entry and exit doses to critical organs,
less tissue volume exposed
1/8
, .
19. What effect does OFD have on a radiograph?: increase OFD causes
magnification, XCP biteblock causes magnification so increase TFD to decrease
magnification
20. What is the Compton Effect?: Outer orbiting electrion, -ion and +ion, only uses
part of its energy; scatter
21. What is the Photoelectric effect?: Inner orbiting electron, -ion and +ion,
uses all of its energy; no scatter.
22. Explain the role of the kVp circuit in the production of X-rays.: kVp controls
speed of electrons from the cathode to the anode
23. How does wavelength effect frequency?: The shorter the wavelength, the higher
the frequency; the longer the wavelength, the lower the frequency.
24. Explain the purpose of the silver halide crystals.: They store radiant energy in an
invisible pattern until processed; size of crystals determines film speed, larger the
crystals the faster the film speed.
25. What error has been made when the film looks clear?: No exposure to radiation
26. What error has been made when the image is darker with an extra set of teeth?:
Double exposure
27. What error has been made when the film is lighter with a visible geometric
pattern?: Film packet was reversed
28. A 0.5 second exposure would produce how many impulses of x-radiation?-
: 30 imp. (60 imp in one second so .5x60=30)
29. The teeth on an x-ray appear stretched out over the film. This was not a result
of bending the film. What caused this and how would it be corrected?:
Elongation caused by too little VA. Correct elongation by increasing VA.
30. How to correct foreshortening: Decrease VA
31. What TFD would produce a radiograph with the least image magnification?
A. 4 in B. 7 in
8 in
16 in: D. 16 in
32. Which term describes the white areas on the processed radiograph?:
Radiopaque
33. Which term best describes an x-ray beam that is composed of a variety of
wavelengths?: Polychromatic
34. Based on the inverse square law, what happens to the intensity of the x-ray
beam when the TFD is doubled?: Intensity is one quarter as great
2/8
