NBDHE Practice 312 Questions and
Answers 2025 - 2026
The x-ray was discovered by
a. Heinrich Geissler
b. Wilhelm Roentgen
c. Johann Hittorf
d. William Crookes -
Ans Wilhelm Roentgen
Which discovery was the precursor to the discovery of x-rays?
A. Beta particles
B. Alpha particles
C. Cathode rays
D. Radioactive materials -
Ans Cathode rays
Which term describes two or more atoms that are joined by a chemical bond?
a. ion
b. ion pair
c. molecule
d. proton -
Ans Molecule
Which is not a type of particulate radiation?
A. Alpha particles
B. Beta particles
C. Protons
D. Nucleons -
Ans Nucleons
Which is the location where x-rays are produced?
A. Positive cathode
B. Positive anode
C. Negative cathode
D. Negative anode -
Ans Positive anode
Which describes scatter radiation?
A. Radiation that exits the tubehead
B. Radiation that is more penetrating than primary radiation
C. Radiation that has been deflected from its path by interaction with matter
D. none of the above -
Ans Radiation that has been deflected from its path by interaction with matter
In dental imaging, the quality of the x ray beam is controlled by?
a. kilovoltage
,b. miliamperage
c. exposure time
d. source-to-receptor distance -
Ans Kilovoltage
Increasing milliamperage results in an increase in:
A. Temperature of filament
B. Mean energy of beam
C. Number of x-rays produced
D. Both A & C -
Ans Temperature of filament and number of x-rays produced
The overall blackness or darkness of an image is termed
a. contrast
b. density
c. overexposure
d. polychromatic -
Ans Density
If the target receptor distance is doubled, the resultant beam will be
a. four times as intense
b. twice as intense
c. half as intense
d. one fourth as intense -
Ans One fourth as intense
The latent period in radiation biology is the time between
a. initial injury and repair
b. subsequent doses of radiation
c. cell rest and cell mitosis
d. exposure to x-radiation and clinical symptoms -
Ans Exposure to x radiation and clinical symptoms
Which factor(s) contributes to radiation injury?
A. Total dose
B. Dose rate
C. Cell sensitivity
D. Age
E. All of the above -
Ans All of the above
The traditional unit for measuring x-ray exposure in air is termed
a. gray
b. coulombs per kilogram
c. rem
d. rad
e. roentgen -
Ans Roentgen
Which is considered radioresistant?
,A. Immature reproductive cells
B. Young bone cells
C. Mature bone cells
D. Epithelial cells
E. None of the above -
Ans Mature bone cells
Which position indicating device is most effective in reducing patient exposure?
A. Conical
B. Rectangular
C. Circular
D. all are equally effective in reducing patient exposure -
Ans Rectangular
Which statement describes the function of a filter in a dental x-ray tube head?
A. It reduces the size and shape of the beam
B. It removes low energy x rays
C. It removes the dose of radiation to the thyroid gland
D. It decreases the mean energy of the beam -
Ans It removes low energy x rays
The dental radiographer can regulate the x ray beam (kVp, mA, time) through the
use of the
a. control panel
b. extension arm
c. console
d. position-indicating device (PID) -
Ans Control panel
One advantage of a film with an emulsion coating on both sides (double-emulsion
film) is that
a. the film requires less radiation exposure to make an image
b. the image produced is less distorted
c. the film has less sensitivity to radiation
d. processing solutions are absorbed more easily -
Ans The film requires less radiation exposure to make an image
The intensifying screen that emits green light and must be used with green sensitive
film is termed
a. calcium tungstate
b. rare earth
c. phosphor
d. rare tungstate -
Ans Rare earth
A dental image that demonstrates many shades of gray is said to have
a. high contrast
b. low contrast
c. high density
d. low density -
, Ans Low contrast
The hydroquinone in the developer brings out the _____ tones, whereas the Elon in
the developer bring out the _____ tones on a dental radiograph.
a. black; white
b. white; black
c. gray; gray
d. white; gray
e. black; gray -
Ans Black; gray
A universal safelight filter such as the GBX-2 by the Carestream Health is
recommended for
a. intraoral films only
b. extraoral screen films only
c. extraoral nonscreen films only
d. intraoral and extraoral films -
Ans Intraoral and extraoral films
Which describes the relationship between the receptor and the long axis of the tooth
in the paralleling technique?
A. The receptor and the tooth are parallel to each other
B. The receptor and the tooth are at right angles to each other
C. The receptor and the tooth are perpendicular to each other
D. The receptor and the tooth are intersecting each other -
Ans The receptor and the tooth are parallel to each other
Too much vertical angulation results in images that are
a. elongated
b. foreshortened
c. overlapped
d. none of the above -
Ans Foreshortened
The zone in which structures are clearly demonstrated on a pano image is termed
the
a. rotation center
b. ghost image
c. focal trough
d. midsagittal plane -
Ans Focal trough
Changing a treatment plan without informing the patient violate which of the
following?
A. Veracity
B. Fidelity
C. Beneficence
D. Societal trust
E. Non-maleficence -
Ans Fidelity
Answers 2025 - 2026
The x-ray was discovered by
a. Heinrich Geissler
b. Wilhelm Roentgen
c. Johann Hittorf
d. William Crookes -
Ans Wilhelm Roentgen
Which discovery was the precursor to the discovery of x-rays?
A. Beta particles
B. Alpha particles
C. Cathode rays
D. Radioactive materials -
Ans Cathode rays
Which term describes two or more atoms that are joined by a chemical bond?
a. ion
b. ion pair
c. molecule
d. proton -
Ans Molecule
Which is not a type of particulate radiation?
A. Alpha particles
B. Beta particles
C. Protons
D. Nucleons -
Ans Nucleons
Which is the location where x-rays are produced?
A. Positive cathode
B. Positive anode
C. Negative cathode
D. Negative anode -
Ans Positive anode
Which describes scatter radiation?
A. Radiation that exits the tubehead
B. Radiation that is more penetrating than primary radiation
C. Radiation that has been deflected from its path by interaction with matter
D. none of the above -
Ans Radiation that has been deflected from its path by interaction with matter
In dental imaging, the quality of the x ray beam is controlled by?
a. kilovoltage
,b. miliamperage
c. exposure time
d. source-to-receptor distance -
Ans Kilovoltage
Increasing milliamperage results in an increase in:
A. Temperature of filament
B. Mean energy of beam
C. Number of x-rays produced
D. Both A & C -
Ans Temperature of filament and number of x-rays produced
The overall blackness or darkness of an image is termed
a. contrast
b. density
c. overexposure
d. polychromatic -
Ans Density
If the target receptor distance is doubled, the resultant beam will be
a. four times as intense
b. twice as intense
c. half as intense
d. one fourth as intense -
Ans One fourth as intense
The latent period in radiation biology is the time between
a. initial injury and repair
b. subsequent doses of radiation
c. cell rest and cell mitosis
d. exposure to x-radiation and clinical symptoms -
Ans Exposure to x radiation and clinical symptoms
Which factor(s) contributes to radiation injury?
A. Total dose
B. Dose rate
C. Cell sensitivity
D. Age
E. All of the above -
Ans All of the above
The traditional unit for measuring x-ray exposure in air is termed
a. gray
b. coulombs per kilogram
c. rem
d. rad
e. roentgen -
Ans Roentgen
Which is considered radioresistant?
,A. Immature reproductive cells
B. Young bone cells
C. Mature bone cells
D. Epithelial cells
E. None of the above -
Ans Mature bone cells
Which position indicating device is most effective in reducing patient exposure?
A. Conical
B. Rectangular
C. Circular
D. all are equally effective in reducing patient exposure -
Ans Rectangular
Which statement describes the function of a filter in a dental x-ray tube head?
A. It reduces the size and shape of the beam
B. It removes low energy x rays
C. It removes the dose of radiation to the thyroid gland
D. It decreases the mean energy of the beam -
Ans It removes low energy x rays
The dental radiographer can regulate the x ray beam (kVp, mA, time) through the
use of the
a. control panel
b. extension arm
c. console
d. position-indicating device (PID) -
Ans Control panel
One advantage of a film with an emulsion coating on both sides (double-emulsion
film) is that
a. the film requires less radiation exposure to make an image
b. the image produced is less distorted
c. the film has less sensitivity to radiation
d. processing solutions are absorbed more easily -
Ans The film requires less radiation exposure to make an image
The intensifying screen that emits green light and must be used with green sensitive
film is termed
a. calcium tungstate
b. rare earth
c. phosphor
d. rare tungstate -
Ans Rare earth
A dental image that demonstrates many shades of gray is said to have
a. high contrast
b. low contrast
c. high density
d. low density -
, Ans Low contrast
The hydroquinone in the developer brings out the _____ tones, whereas the Elon in
the developer bring out the _____ tones on a dental radiograph.
a. black; white
b. white; black
c. gray; gray
d. white; gray
e. black; gray -
Ans Black; gray
A universal safelight filter such as the GBX-2 by the Carestream Health is
recommended for
a. intraoral films only
b. extraoral screen films only
c. extraoral nonscreen films only
d. intraoral and extraoral films -
Ans Intraoral and extraoral films
Which describes the relationship between the receptor and the long axis of the tooth
in the paralleling technique?
A. The receptor and the tooth are parallel to each other
B. The receptor and the tooth are at right angles to each other
C. The receptor and the tooth are perpendicular to each other
D. The receptor and the tooth are intersecting each other -
Ans The receptor and the tooth are parallel to each other
Too much vertical angulation results in images that are
a. elongated
b. foreshortened
c. overlapped
d. none of the above -
Ans Foreshortened
The zone in which structures are clearly demonstrated on a pano image is termed
the
a. rotation center
b. ghost image
c. focal trough
d. midsagittal plane -
Ans Focal trough
Changing a treatment plan without informing the patient violate which of the
following?
A. Veracity
B. Fidelity
C. Beneficence
D. Societal trust
E. Non-maleficence -
Ans Fidelity
