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BU DENTAL RADIOLOGY FINAL PRACTICE
EXAM 2026 JUST RELEASED VERSION
SECTION 1: Radiation Physics & X-Ray Production (Q1–Q20)
Q1. X-rays are produced primarily when:
A. Electrons strike the filament
B. Electrons strike the tungsten target
C. Photons strike atoms
D. Heat dissipates
Answer: B
Rationale: High-speed electrons hit the tungsten target
(anode), producing x-rays. Heat is generated simultaneously.
Q2. Bremsstrahlung radiation is caused by:
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A. Electron shell transitions
B. Sudden deceleration of electrons near nuclei
C. Heat production
D. Filtration
Answer: B
Rationale: “Braking radiation” occurs when an electron slows
near a nucleus, releasing energy as an x-ray photon.
Q3. Characteristic radiation occurs when:
A. Electrons lose speed near nuclei
B. An inner-shell electron is ejected and an outer-shell electron
fills the vacancy
C. Heat dissipates
D. Filtration removes low-energy photons
Answer: B
Rationale: Characteristic radiation is specific to the atomic
structure of the target material.
Q4. The primary purpose of filtration in dental x-ray units is:
A. Increase radiation dose
B. Remove low-energy, non-penetrating photons
C. Increase image density
D. Improve contrast
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Answer: B
Rationale: Low-energy x-rays increase patient dose without
improving image quality.
Q5. Kilovoltage peak (kVp) controls:
A. Number of photons only
B. Density only
C. Beam energy (penetration) and image contrast
D. Exposure time only
Answer: C
Rationale: Higher kVp increases penetration and reduces image
contrast.
Q6. Milliamperage (mA) primarily controls:
A. Beam quality
B. Number of photons produced
C. Contrast
D. Wavelength
Answer: B
Rationale: mA controls the quantity (intensity) of x-rays, not
energy.
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Q7. The cathode in a dental x-ray tube contains:
A. The tungsten target
B. Step-up transformer
C. Filament and focusing cup
D. Collimator
Answer: C
Rationale: Electrons originate at the filament, which is heated,
then focused by the focusing cup.
Q8. The anode is typically made of:
A. Copper
B. Lead
C. Tungsten
D. Aluminum
Answer: C
Rationale: Tungsten’s high atomic number and melting point
make it ideal for x-ray production.
Q9. Heat production in the x-ray tube accounts for
approximately:
A. 1%
B. 10%
BU DENTAL RADIOLOGY FINAL PRACTICE
EXAM 2026 JUST RELEASED VERSION
SECTION 1: Radiation Physics & X-Ray Production (Q1–Q20)
Q1. X-rays are produced primarily when:
A. Electrons strike the filament
B. Electrons strike the tungsten target
C. Photons strike atoms
D. Heat dissipates
Answer: B
Rationale: High-speed electrons hit the tungsten target
(anode), producing x-rays. Heat is generated simultaneously.
Q2. Bremsstrahlung radiation is caused by:
,2
A. Electron shell transitions
B. Sudden deceleration of electrons near nuclei
C. Heat production
D. Filtration
Answer: B
Rationale: “Braking radiation” occurs when an electron slows
near a nucleus, releasing energy as an x-ray photon.
Q3. Characteristic radiation occurs when:
A. Electrons lose speed near nuclei
B. An inner-shell electron is ejected and an outer-shell electron
fills the vacancy
C. Heat dissipates
D. Filtration removes low-energy photons
Answer: B
Rationale: Characteristic radiation is specific to the atomic
structure of the target material.
Q4. The primary purpose of filtration in dental x-ray units is:
A. Increase radiation dose
B. Remove low-energy, non-penetrating photons
C. Increase image density
D. Improve contrast
,3
Answer: B
Rationale: Low-energy x-rays increase patient dose without
improving image quality.
Q5. Kilovoltage peak (kVp) controls:
A. Number of photons only
B. Density only
C. Beam energy (penetration) and image contrast
D. Exposure time only
Answer: C
Rationale: Higher kVp increases penetration and reduces image
contrast.
Q6. Milliamperage (mA) primarily controls:
A. Beam quality
B. Number of photons produced
C. Contrast
D. Wavelength
Answer: B
Rationale: mA controls the quantity (intensity) of x-rays, not
energy.
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Q7. The cathode in a dental x-ray tube contains:
A. The tungsten target
B. Step-up transformer
C. Filament and focusing cup
D. Collimator
Answer: C
Rationale: Electrons originate at the filament, which is heated,
then focused by the focusing cup.
Q8. The anode is typically made of:
A. Copper
B. Lead
C. Tungsten
D. Aluminum
Answer: C
Rationale: Tungsten’s high atomic number and melting point
make it ideal for x-ray production.
Q9. Heat production in the x-ray tube accounts for
approximately:
A. 1%
B. 10%
