CGSB NDT LEVEL 2 CERTIFICATION EXAM 2026 | NEWEST
ACTUAL EXAM COMPLETE 300 QESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) |
ALREADY GRADED A+
SECTION A: ADVANCED NDT PRINCIPLES AND PHYSICS (Questions 1-30)
Question 1
What is the "inverse square law" in radiography?
A. Intensity is inversely proportional to the square of the distance from the source
B. Intensity is directly proportional to distance
C. Intensity is inversely proportional to distance
D. Intensity is independent of distance
Correct Answer: A
Rationale: The inverse square law states that radiation intensity (I) decreases with
the square of the distance (d): I₁ / I₂ = (d₂ / d₁)². This is critical for calculating
exposure times and safe working distances.
Question 2
What is "beam divergence" in UT?
A. The spreading of the ultrasonic beam as it travels through the material
B. The focusing of the beam
C. The attenuation of the beam
D. The reflection of the beam
Correct Answer: A
Rationale: Beam divergence (or beam spread) is the natural spreading of the
ultrasonic beam as it propagates. It is influenced by transducer diameter and
frequency. Smaller transducers and lower frequencies diverge more.
Question 3
1
,What is the difference between "amplitude" and "intensity" in ultrasound?
A. Amplitude is the height of the wave; intensity is the power per unit area
(proportional to amplitude squared)
B. Amplitude is the power; intensity is the height
C. They are the same
D. Amplitude is measured in decibels; intensity is measured in hertz
Correct Answer: A
Rationale: Amplitude is the peak displacement of the wave (voltage). Intensity is
the energy per unit area and is proportional to the square of the amplitude. Both
are used to characterize signals.
Question 4
What is the "near field" length (N) of a transducer determined by?
A. N = D² / (4λ)
B. N = D² × (4λ)
C. N = D / (2λ)
D. N = λ / D²
Correct Answer: A
Rationale: The near field length (N) = D² / (4λ), where D is the transducer
diameter and λ is the wavelength. The near field is the region of complex
interference; flaw sizing is best performed in the far field.
Question 5
What is the effect of increasing the frequency of an eddy current test?
A. It decreases skin depth and increases sensitivity to surface defects
B. It increases skin depth
C. It has no effect on skin depth
D. It reduces sensitivity to surface defects
Correct Answer: A
2
,Rationale: Higher frequency reduces skin depth (less penetration) but improves
the resolution of surface defects because the eddy currents are more
concentrated near the surface. This is the classic trade-off in ET.
Question 6
What does "acoustic impedance" (Z) represent in UT?
A. Z = ρ × v (density × velocity)
B. Z = ρ / v
C. Z = v / ρ
D. Z = ρ + v
Correct Answer: A
Rationale: Acoustic impedance (Z) is the product of material density (ρ) and sound
velocity (v). The difference in impedance between two materials determines the
reflection coefficient at their interface.
Question 7
What percentage of sound intensity is reflected at a boundary between two
materials with a large impedance mismatch (e.g., steel-air)?
A. Nearly 100%
B. 0%
C. 50%
D. 10%
Correct Answer: A
Rationale: The reflection coefficient R = ((Z₂ - Z₁) / (Z₂ + Z₁))². Steel has very high
impedance; air has very low impedance. The mismatch is so large that nearly all
energy is reflected, which is why couplant is needed to eliminate air gaps.
Question 8
In radiography, what is the "half-value layer" (HVL)?
A. The thickness of a material that reduces radiation intensity by 50%
B. The thickness that reduces intensity by 90%
3
, C. The maximum penetration of the radiation
D. The thickness required for maximum film density
Correct Answer: A
Rationale: HVL is the thickness of a given absorber that reduces the incident
radiation intensity to one-half. It is a measure of the penetrating power of the
radiation and depends on the energy and material.
Question 9
What is "mode conversion" in UT?
A. The change of wave mode (e.g., longitudinal to shear) when a wave strikes an
interface at an angle
B. The change of frequency
C. The change of amplitude
D. The change of transducer type
Correct Answer: A
Rationale: Mode conversion occurs when an ultrasonic wave strikes a boundary at
an angle. Part of the energy may convert from longitudinal to shear (or vice
versa). This is fundamental to angle-beam UT.
Question 10
Which of the following best describes the relationship between wavelength (λ),
frequency (f), and velocity (v) in ultrasonic testing?
A. v = f × λ
B. v = λ / f
C. f = v × λ
D. λ = v × f
Correct Answer: A
Rationale: The fundamental wave equation is v = f × λ. Velocity is constant for a
given material and mode. Higher frequency results in shorter wavelength, which
improves resolution but reduces penetration.
4
ACTUAL EXAM COMPLETE 300 QESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) |
ALREADY GRADED A+
SECTION A: ADVANCED NDT PRINCIPLES AND PHYSICS (Questions 1-30)
Question 1
What is the "inverse square law" in radiography?
A. Intensity is inversely proportional to the square of the distance from the source
B. Intensity is directly proportional to distance
C. Intensity is inversely proportional to distance
D. Intensity is independent of distance
Correct Answer: A
Rationale: The inverse square law states that radiation intensity (I) decreases with
the square of the distance (d): I₁ / I₂ = (d₂ / d₁)². This is critical for calculating
exposure times and safe working distances.
Question 2
What is "beam divergence" in UT?
A. The spreading of the ultrasonic beam as it travels through the material
B. The focusing of the beam
C. The attenuation of the beam
D. The reflection of the beam
Correct Answer: A
Rationale: Beam divergence (or beam spread) is the natural spreading of the
ultrasonic beam as it propagates. It is influenced by transducer diameter and
frequency. Smaller transducers and lower frequencies diverge more.
Question 3
1
,What is the difference between "amplitude" and "intensity" in ultrasound?
A. Amplitude is the height of the wave; intensity is the power per unit area
(proportional to amplitude squared)
B. Amplitude is the power; intensity is the height
C. They are the same
D. Amplitude is measured in decibels; intensity is measured in hertz
Correct Answer: A
Rationale: Amplitude is the peak displacement of the wave (voltage). Intensity is
the energy per unit area and is proportional to the square of the amplitude. Both
are used to characterize signals.
Question 4
What is the "near field" length (N) of a transducer determined by?
A. N = D² / (4λ)
B. N = D² × (4λ)
C. N = D / (2λ)
D. N = λ / D²
Correct Answer: A
Rationale: The near field length (N) = D² / (4λ), where D is the transducer
diameter and λ is the wavelength. The near field is the region of complex
interference; flaw sizing is best performed in the far field.
Question 5
What is the effect of increasing the frequency of an eddy current test?
A. It decreases skin depth and increases sensitivity to surface defects
B. It increases skin depth
C. It has no effect on skin depth
D. It reduces sensitivity to surface defects
Correct Answer: A
2
,Rationale: Higher frequency reduces skin depth (less penetration) but improves
the resolution of surface defects because the eddy currents are more
concentrated near the surface. This is the classic trade-off in ET.
Question 6
What does "acoustic impedance" (Z) represent in UT?
A. Z = ρ × v (density × velocity)
B. Z = ρ / v
C. Z = v / ρ
D. Z = ρ + v
Correct Answer: A
Rationale: Acoustic impedance (Z) is the product of material density (ρ) and sound
velocity (v). The difference in impedance between two materials determines the
reflection coefficient at their interface.
Question 7
What percentage of sound intensity is reflected at a boundary between two
materials with a large impedance mismatch (e.g., steel-air)?
A. Nearly 100%
B. 0%
C. 50%
D. 10%
Correct Answer: A
Rationale: The reflection coefficient R = ((Z₂ - Z₁) / (Z₂ + Z₁))². Steel has very high
impedance; air has very low impedance. The mismatch is so large that nearly all
energy is reflected, which is why couplant is needed to eliminate air gaps.
Question 8
In radiography, what is the "half-value layer" (HVL)?
A. The thickness of a material that reduces radiation intensity by 50%
B. The thickness that reduces intensity by 90%
3
, C. The maximum penetration of the radiation
D. The thickness required for maximum film density
Correct Answer: A
Rationale: HVL is the thickness of a given absorber that reduces the incident
radiation intensity to one-half. It is a measure of the penetrating power of the
radiation and depends on the energy and material.
Question 9
What is "mode conversion" in UT?
A. The change of wave mode (e.g., longitudinal to shear) when a wave strikes an
interface at an angle
B. The change of frequency
C. The change of amplitude
D. The change of transducer type
Correct Answer: A
Rationale: Mode conversion occurs when an ultrasonic wave strikes a boundary at
an angle. Part of the energy may convert from longitudinal to shear (or vice
versa). This is fundamental to angle-beam UT.
Question 10
Which of the following best describes the relationship between wavelength (λ),
frequency (f), and velocity (v) in ultrasonic testing?
A. v = f × λ
B. v = λ / f
C. f = v × λ
D. λ = v × f
Correct Answer: A
Rationale: The fundamental wave equation is v = f × λ. Velocity is constant for a
given material and mode. Higher frequency results in shorter wavelength, which
improves resolution but reduces penetration.
4
