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CGSB ULTRASONIC TESTING (UT) LEVEL 1 EXAM
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) Q & A 2026 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of ultrasonic testing? A. Measure temperature B. Detect internal flaws in materials C. Paint surface coatings D. Measure electrical resistance Rationale: UT uses high-frequency sound waves to detect internal discontinuities. Correct Answer: B 2. Ultrasonic waves used in NDT are typically: A. Infrared waves B. Radio waves C. High-frequency sound waves D. Light waves Rationale: UT uses mechanical sound waves above human hearing range. Correct Answer: C 3. The standard unit of frequency in UT is: A. Decibel B. Hertz
C. Pascal D. Tesla Rationale: Frequency is measured in cycles per second (Hz). Correct Answer: B
4. The most commonly used UT wave mode for flaw detection is: A. Surface waves B. Longitudinal waves C. Transverse waves D. Rayleigh waves Rationale: Longitudinal waves penetrate deeply into materials. Correct Answer: B 5. A couplant in UT is used to: A. Increase temperature B. Improve electrical conductivity C. Eliminate air gaps between probe and test surface D. Harden the surface Rationale: Couplant ensures efficient transmission of sound energy. Correct Answer: C 6. What material is commonly used as a couplant?
9. The speed of sound in a material depends mainly on: A. Color of material B. Density and elasticity C. Temperature only D. Electrical resistance Rationale: Material properties determine wave velocity. Correct Answer: B 10. The main purpose of calibration in UT is to: A. Change probe shape B. Ensure accurate measurement readings C. Increase sound frequency D. Reduce operator fatigue Rationale: Calibration ensures measurement accuracy and reliability. Correct Answer: B 11. A flaw that reflects ultrasonic waves is called a: A. Reflector B. Defect C. Scatterer D. Absorber Rationale: Discontinuities reflect sound waves back to the probe. Correct Answer: A
12. The A-scan display shows: A. Color images B. 2D surface map C. Amplitude vs time signal D. Temperature graph Rationale: A-scan represents signal amplitude over time. Correct Answer: C 13. In UT, the couplant is necessary because: A. Sound cannot travel through air efficiently B. It increases frequency C. It reduces probe size D. It increases hardness Rationale: Air gaps reflect ultrasonic waves completely. Correct Answer: A 14. What is attenuation in UT? A. Increase in signal strength B. Loss of wave energy as it travels C. Increase in temperature D. Wave reflection only Rationale: Sound weakens due to scattering and absorption. Correct Answer: B
Rationale: UT typically uses MHz frequency range. Correct Answer: A
18. Higher frequency UT waves provide: A. Greater penetration, lower resolution B. Lower penetration, higher resolution C. No penetration D. Electrical output Rationale: High frequency improves detail but reduces depth. Correct Answer: B 19. Lower frequency UT waves provide: A. Better resolution B. Deeper penetration C. No signal D. Higher noise Rationale: Lower frequency travels deeper into materials. Correct Answer: B 20. The main purpose of a pulse-echo system is to: A. Measure electrical resistance B. Send and receive reflected ultrasonic signals C. Heat materials D. Measure pressure only
Rationale: It detects reflections from flaws or boundaries. Correct Answer: B
21. A dead zone in UT is: A. Area with no electricity B. Region where defects cannot be detected near surface C. Calibration zone D. Weld zone only Rationale: Initial pulse masks near-surface reflections. Correct Answer: B 22. What causes signal reflection in UT? A. Density change B. Color change C. Magnetic field D. Electrical resistance Rationale: Acoustic impedance differences cause reflections. Correct Answer: A 23. Acoustic impedance is defined as: A. Voltage × Current B. Density × Sound velocity C. Pressure × Temperature D. Mass × Time
Rationale: Interpretation requires training and experience. Correct Answer: B
27. Which material is difficult to test using UT? A. Steel B. Aluminum C. Plastics D. Cast iron with coarse grains Rationale: Coarse grains scatter sound waves. Correct Answer: D 28. The main function of a UT screen display is to: A. Show electrical voltage B. Display reflected signals C. Measure hardness D. Store chemicals Rationale: It visually represents echo signals. Correct Answer: B 29. Gain control in UT adjusts: A. Probe size B. Signal amplitude C. Material density D. Frequency
Rationale: Gain amplifies or reduces signal strength. Correct Answer: B
30. The first signal on an A-scan is called: A. Backwall echo B. Initial pulse C. Defect signal D. Noise signal Rationale: It represents probe emission. Correct Answer: B 31. Backwall echo represents: A. Surface defect B. Bottom of material reflection C. Electrical noise D. Calibration error Rationale: It comes from the far boundary of material. Correct Answer: B 32. Beam spread refers to: A. Increase in signal strength B. Divergence of ultrasonic beam C. Reduction in temperature D. Increase in density
Rationale: Particle motion is perpendicular to propagation. Correct Answer: B
36. Longitudinal waves move particles: A. Perpendicular to direction B. Parallel to direction C. Circular motion D. No motion Rationale: Particle vibration is in wave direction. Correct Answer: B 37. Resolution in UT refers to: A. Color clarity B. Ability to distinguish two nearby reflectors C. Temperature accuracy D. Electrical output Rationale: Higher resolution separates close defects. Correct Answer: B 38. Coupling loss occurs due to: A. Good contact B. Poor sound transmission at interface C. High frequency D. High gain
Rationale: Air gaps reduce energy transfer. Correct Answer: B
39. The main component of a UT system is: A. Radiation source B. Transducer C. Film processor D. Magnet Rationale: Transducer generates and receives waves. Correct Answer: B 40. The purpose of a reference standard in UT is to: A. Increase signal noise B. Provide known defect size for calibration C. Heat material D. Reduce frequency Rationale: Standards ensure measurement accuracy. Correct Answer: B 41. Which of the following is NOT an ultrasonic testing method? A. Pulse-echo B. Through-transmission C. Radiographic testing
D. Generate sound Rationale: It relates signal time to depth. Correct Answer: B
45. Which factor affects ultrasonic wave penetration most? A. Color B. Frequency and material attenuation C. Surface paint D. Operator speed Rationale: Higher attenuation reduces penetration. Correct Answer: B 46. A defect lying parallel to sound beam is: A. Easily detected B. Difficult to detect C. Always visible D. Magnetic Rationale: Parallel defects reflect little energy back. Correct Answer: B 47. Angle beam probes are used to detect: A. Surface contamination only B. Subsurface and weld defects C. Paint thickness
D. Temperature changes Rationale: They inspect welds and angled flaws. Correct Answer: B
48. The angle of refraction is governed by: A. Newton’s law B. Snell’s law C. Hooke’s law D. Boyle’s law Rationale: Snell’s law explains wave bending. Correct Answer: B 49. What happens when ultrasonic wave hits a boundary? A. It disappears B. It reflects, refracts, or transmits C. It becomes heat D. It becomes electric current Rationale: Energy splits depending on material interface. Correct Answer: B 50. Resolution in UT improves when: A. Frequency increases B. Frequency decreases C. Couplant is removed
D. Heat material Rationale: Ensures system accuracy using known references. Correct Answer: B
54. A DAC curve in UT is used to: A. Measure voltage B. Compare signal amplitudes at different depths C. Change frequency D. Increase couplant efficiency Rationale: Distance Amplitude Correction compensates signal loss. Correct Answer: B 55. What does a reflector in UT do? A. Absorbs sound B. Reflects ultrasonic energy C. Amplifies signal D. Reduces noise Rationale: Discontinuities act as reflectors. Correct Answer: B 56. Which defect type is easiest to detect with UT? A. Very small porosity clusters B. Large planar cracks
C. Surface rust D. Paint scratches Rationale: Planar defects reflect strong signals. Correct Answer: B
57. The main function of a pulser in UT equipment is to: A. Receive signals B. Generate electrical pulses C. Measure thickness D. Reduce noise Rationale: It excites the transducer. Correct Answer: B 58. The receiver in UT system: A. Sends pulses B. Converts echoes to electrical signals C. Produces couplant D. Calibrates equipment Rationale: It processes reflected signals. Correct Answer: B 59. Noise in UT is: A. Useful signal B. Unwanted signals interfering with interpretation
