MEAGHAN PIRETTI STUDY GUIDE RADIOGRAPHIC
POSITIONING & PROCEDURES COMPLETE CERTIFICATION
PRACTICE EXAM 120 Multiple Choice Questions with Answers
and Rationales
SECTION I: IMAGE PRODUCTION & X-RAY TUBE COMPONENTS
1. Which side of the x-ray tube is positive?
A) Cathode
B) Anode
C) Filament
D) Stator
Correct Answer: B) Anode
Rationale: The anode serves as the positive electrode in the x-ray tube, attracting
electrons from the cathode and converting their kinetic energy into x-ray photons
and heat through interactions with the tungsten target material.
2. What is the role of the glass envelope in the x-ray tube?
A) To focus the electron beam
B) To provide structural support for the rotor
C) To contain and maintain the vacuum
D) To prevent heat from escaping
Correct Answer: C) To contain and maintain the vacuum
Rationale: The glass envelope provides a sealed, evacuated environment that
prevents electron collisions with gas molecules, ensuring efficient electron flow
from cathode to anode without scattering or arcing.
3. Which end of the x-ray tube contains the filament and focusing cup?
, A) Anode end
B) Stator end
C) Cathode end
D) Rotor end
Correct Answer: C) Cathode end
Rationale: The cathode end houses the filament that undergoes thermionic
emission and the focusing cup that shapes and directs the electron stream toward
the anode target for x-ray production.
4. What are the two types of anodes used in x-ray tubes?
A) Fixed and variable
B) Rotating and stationary
C) Copper and tungsten
D) Conductive and insulative
Correct Answer: B) Rotating and stationary
Rationale: Rotating anodes dissipate heat over a larger surface area enabling
higher tube loading capacities, while stationary anodes are simpler designs used
in portable or dental units with lower heat requirements.
5. Why is tungsten the chosen material for the anode?
A) It has a low melting point
B) It is inexpensive and easy to machine
C) It has a high atomic number and high melting point
D) It conducts electricity better than copper
Correct Answer: C) It has a high atomic number and high melting point
Rationale: Tungsten's high atomic number (74) increases the probability of x-ray
production, while its high melting point (3370°C) allows the anode to withstand
the intense heat generated during high-energy exposures without damage.
,6. What is the purpose of the focusing cup in the x-ray tube?
A) To increase the temperature of the filament
B) To shape and direct the electron stream toward the anode
C) To absorb heat from the anode
D) To filter out low-energy x-ray photons
Correct Answer: B) To shape and direct the electron stream toward the anode
Rationale: The focusing cup, which is negatively charged, surrounds the filament
and electrostatically focuses the electron beam into a narrow stream directed at
the anode target, improving x-ray production efficiency.
7. What is the Line Focus Principle?
A) The relationship between mA and exposure time
B) The relationship between the actual focal spot and the effective focal spot
C) The relationship between kVp and beam quality
D) The relationship between SID and OID
Correct Answer: B) The relationship between the actual focal spot and the
effective focal spot
Rationale: The Line Focus Principle states that the effective focal spot size is
smaller than the actual focal spot size due to the anode angle. This allows for
improved spatial resolution while maintaining heat dissipation capacity.
8. Which of the following is the negative side of the x-ray tube?
A) Cathode
B) Anode
C) Stator
D) Rotor
Correct Answer: A) Cathode
, Rationale: The cathode is the negative side of the x-ray tube. It contains the
filament that produces electrons through thermionic emission.
9. The induction motor in a rotating anode tube is responsible for:
A) Generating x-ray photons
B) Rotating the anode during exposure
C) Focusing the electron beam
D) Rectifying the electrical current
Correct Answer: B) Rotating the anode during exposure
Rationale: The induction motor, consisting of the stator and rotor, rotates the
anode at high speeds (typically 3,600–10,000 RPM) during exposure to distribute
heat over a larger surface area, preventing localized melting of the anode.
10. Which of the following is NOT a component of the cathode assembly?
A) Filament
B) Focusing cup
C) Anode disk
D) Connecting wires
Correct Answer: C) Anode disk
Rationale: The anode disk is part of the anode assembly, not the cathode. The
cathode assembly consists of the filament, focusing cup, and connecting wires.
11. What is the primary function of the stator in a rotating anode tube?
A) To emit electrons
B) To focus the electron beam
C) To provide the magnetic field that rotates the rotor
D) To absorb heat from the anode
POSITIONING & PROCEDURES COMPLETE CERTIFICATION
PRACTICE EXAM 120 Multiple Choice Questions with Answers
and Rationales
SECTION I: IMAGE PRODUCTION & X-RAY TUBE COMPONENTS
1. Which side of the x-ray tube is positive?
A) Cathode
B) Anode
C) Filament
D) Stator
Correct Answer: B) Anode
Rationale: The anode serves as the positive electrode in the x-ray tube, attracting
electrons from the cathode and converting their kinetic energy into x-ray photons
and heat through interactions with the tungsten target material.
2. What is the role of the glass envelope in the x-ray tube?
A) To focus the electron beam
B) To provide structural support for the rotor
C) To contain and maintain the vacuum
D) To prevent heat from escaping
Correct Answer: C) To contain and maintain the vacuum
Rationale: The glass envelope provides a sealed, evacuated environment that
prevents electron collisions with gas molecules, ensuring efficient electron flow
from cathode to anode without scattering or arcing.
3. Which end of the x-ray tube contains the filament and focusing cup?
, A) Anode end
B) Stator end
C) Cathode end
D) Rotor end
Correct Answer: C) Cathode end
Rationale: The cathode end houses the filament that undergoes thermionic
emission and the focusing cup that shapes and directs the electron stream toward
the anode target for x-ray production.
4. What are the two types of anodes used in x-ray tubes?
A) Fixed and variable
B) Rotating and stationary
C) Copper and tungsten
D) Conductive and insulative
Correct Answer: B) Rotating and stationary
Rationale: Rotating anodes dissipate heat over a larger surface area enabling
higher tube loading capacities, while stationary anodes are simpler designs used
in portable or dental units with lower heat requirements.
5. Why is tungsten the chosen material for the anode?
A) It has a low melting point
B) It is inexpensive and easy to machine
C) It has a high atomic number and high melting point
D) It conducts electricity better than copper
Correct Answer: C) It has a high atomic number and high melting point
Rationale: Tungsten's high atomic number (74) increases the probability of x-ray
production, while its high melting point (3370°C) allows the anode to withstand
the intense heat generated during high-energy exposures without damage.
,6. What is the purpose of the focusing cup in the x-ray tube?
A) To increase the temperature of the filament
B) To shape and direct the electron stream toward the anode
C) To absorb heat from the anode
D) To filter out low-energy x-ray photons
Correct Answer: B) To shape and direct the electron stream toward the anode
Rationale: The focusing cup, which is negatively charged, surrounds the filament
and electrostatically focuses the electron beam into a narrow stream directed at
the anode target, improving x-ray production efficiency.
7. What is the Line Focus Principle?
A) The relationship between mA and exposure time
B) The relationship between the actual focal spot and the effective focal spot
C) The relationship between kVp and beam quality
D) The relationship between SID and OID
Correct Answer: B) The relationship between the actual focal spot and the
effective focal spot
Rationale: The Line Focus Principle states that the effective focal spot size is
smaller than the actual focal spot size due to the anode angle. This allows for
improved spatial resolution while maintaining heat dissipation capacity.
8. Which of the following is the negative side of the x-ray tube?
A) Cathode
B) Anode
C) Stator
D) Rotor
Correct Answer: A) Cathode
, Rationale: The cathode is the negative side of the x-ray tube. It contains the
filament that produces electrons through thermionic emission.
9. The induction motor in a rotating anode tube is responsible for:
A) Generating x-ray photons
B) Rotating the anode during exposure
C) Focusing the electron beam
D) Rectifying the electrical current
Correct Answer: B) Rotating the anode during exposure
Rationale: The induction motor, consisting of the stator and rotor, rotates the
anode at high speeds (typically 3,600–10,000 RPM) during exposure to distribute
heat over a larger surface area, preventing localized melting of the anode.
10. Which of the following is NOT a component of the cathode assembly?
A) Filament
B) Focusing cup
C) Anode disk
D) Connecting wires
Correct Answer: C) Anode disk
Rationale: The anode disk is part of the anode assembly, not the cathode. The
cathode assembly consists of the filament, focusing cup, and connecting wires.
11. What is the primary function of the stator in a rotating anode tube?
A) To emit electrons
B) To focus the electron beam
C) To provide the magnetic field that rotates the rotor
D) To absorb heat from the anode
