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CGSB ULTRASONIC TESTING (UT) LEVEL 2 EXAM
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) Q & A 2026 |INSTANT DOWNLOAD PDF
1. Which wave mode is most commonly used in ultrasonic flaw detection in metals? A. Surface waves B. Longitudinal waves C. Rayleigh waves D. Plate waves Rationale: Longitudinal waves travel efficiently in solids and provide deep penetration and good flaw detection capability. Correct Answer: B. Longitudinal waves 2. What is the main purpose of couplant in ultrasonic testing? A. Increase signal amplitude B. Reduce electrical noise C. Eliminate air gap between probe and test surface D. Increase frequency Rationale: Air gaps reflect ultrasound; couplant ensures efficient sound transmission. Correct Answer: C. Eliminate air gap between probe and test surface
3. Frequency increase in ultrasonic testing results in: A. Greater penetration and lower resolution B. Lower penetration and higher resolution C. No change in penetration D. Increased wavelength Rationale: Higher frequency improves resolution but reduces penetration depth. Correct Answer: B. Lower penetration and higher resolution 4. What unit is used to express sound velocity in materials? A. Hz B. m/s C. dB D. Ohm Rationale: Sound velocity is measured as distance per time. Correct Answer: B. m/s 5. The principle of ultrasonic testing is based on: A. Magnetic field induction B. Reflection and transmission of sound waves C. Heat conduction D. Electrical resistance Rationale: UT uses sound wave reflection from discontinuities. Correct Answer: B. Reflection and transmission of sound waves
Rationale: They generate and receive ultrasonic waves. Correct Answer: B. Convert electrical energy to mechanical vibrations
9. The unit of ultrasonic frequency is: A. Meter B. Hertz C. Joule D. Pascal Rationale: Frequency is cycles per second. Correct Answer: B. Hertz 10. What happens when ultrasound hits a crack perpendicular to beam direction? A. No reflection occurs B. Maximum reflection occurs C. Absorption only D. Refraction only Rationale: Perpendicular flaws reflect maximum energy back to probe. Correct Answer: B. Maximum reflection occurs 11. Which coupling medium is commonly used in ultrasonic testing?
A. Oil B. Mercury C. Water D. Air Rationale: Oil or water provides good acoustic transmission. Correct Answer: A. Oil
12. A transducer converts: A. Sound to heat B. Electrical energy to sound energy C. Light to sound D. Pressure to heat Rationale: Transducers are energy converters in UT systems. Correct Answer: B. Electrical energy to sound energy 13. Beam divergence increases when: A. Frequency increases B. Wavelength decreases C. Frequency decreases D. Amplitude increases Rationale: Lower frequency results in wider beam spread. Correct Answer: C. Frequency decreases
Rationale: Energy is lost due to scattering and absorption. Correct Answer: B. Reduction in signal strength
17. Which display is commonly used in UT equipment? A. L-scan B. A-scan C. X-ray image D. Digital chart only Rationale: A-scan shows amplitude vs time. Correct Answer: B. A-scan 18. Sound travels fastest in: A. Air B. Water C. Steel D. Vacuum Rationale: Solids have tightly packed molecules. Correct Answer: C. Steel 19. Calibration blocks in UT are used to: A. Increase signal strength B. Standardize measurements and accuracy
C. Reduce noise D. Increase frequency Rationale: They ensure equipment accuracy and reliability. Correct Answer: B. Standardize measurements and accuracy
20. Refraction occurs when a wave: A. Is absorbed completely B. Changes direction entering another medium C. Reflects back fully D. Stops propagation Rationale: Change in medium causes wave bending. Correct Answer: B. Changes direction entering another medium 21. What is the purpose of time base calibration in UT? A. Increase amplitude B. Set correct distance scale C. Reduce noise D. Change frequency Rationale: Time base calibration ensures accurate depth/distance measurement. Correct Answer: B. Set correct distance scale 22. What causes ultrasonic signal loss in materials?
A. Increase voltage B. Generate shear waves C. Reduce noise D. Amplify signal Correct Answer: B. Generate shear waves
26. Which wave mode is typically used for surface crack detection? A. Longitudinal B. Shear C. Surface waves D. Bulk waves Correct Answer: C. Surface waves 27. What does A-scan display show? A. Image of weld B. Signal amplitude vs time C. Color map D. Frequency spectrum only Correct Answer: B. Signal amplitude vs time 28. Which factor affects acoustic impedance?
A. Frequency B. Material density and velocity C. Probe size D. Couplant type Correct Answer: B. Material density and velocity
29. Acoustic impedance is important because it determines: A. Beam width B. Reflection at interfaces C. Frequency D. Voltage Correct Answer: B. Reflection at interfaces 30. What happens when impedance mismatch is high? A. No reflection B. Maximum reflection C. No transmission D. Zero attenuation Correct Answer: B. Maximum reflection 31. Which calibration block is commonly used in UT? A. ISO block B. IIW block
Correct Answer: C. Very small near-surface cracks
35. What is the main function of pulser in UT equipment? A. Receive signals B. Generate high-voltage electrical pulses C. Display signals D. Measure thickness Correct Answer: B. Generate high-voltage electrical pulses 36. What is the function of receiver in UT system? A. Generate sound B. Convert echoes into electrical signals C. Increase frequency D. Reduce attenuation Correct Answer: B. Convert echoes into electrical signals 37. Which of the following is NOT a UT method? A. Pulse-echo B. Through transmission C. Radiographic testing D. Immersion testing Correct Answer: C. Radiographic testing
38. Which phenomenon explains wave bending at interfaces? A. Reflection B. Refraction C. Diffraction D. Absorption Correct Answer: B. Refraction 39. What is the main advantage of immersion testing? A. No couplant needed B. High precision scanning C. No calibration required D. No signal loss Correct Answer: B. High precision scanning 40. What is DAC in UT? A. Digital amplitude control B. Distance amplitude correction C. Defect assessment code D. Data analysis curve Correct Answer: B. Distance amplitude correction 41. DAC curve is used for:
C. 5900 m/s D. 300 m/s Correct Answer: C. 5900 m/s
45. Which wave travels slowest in solids? A. Longitudinal B. Shear C. Surface D. All same Correct Answer: B. Shear 46. What causes scattering in UT signals? A. Smooth surfaces B. Grain structure C. Couplant D. Frequency only Correct Answer: B. Grain structure 47. What is a flaw echo? A. Noise signal B. Reflection from defect C. Calibration signal D. Couplant signal
Correct Answer: B. Reflection from defect
48. Backwall echo indicates: A. Surface crack B. Far surface reflection C. Noise D. Probe failure Correct Answer: B. Far surface reflection 49. Loss of backwall echo may indicate: A. Good material B. Internal defect C. Increased frequency D. Better coupling Correct Answer: B. Internal defect 50. What is resolution in UT? A. Ability to detect depth only B. Ability to distinguish two close reflectors C. Signal strength D. Couplant quality Correct Answer: B. Ability to distinguish two close reflectors
A. Through transmission B. Pulse-echo C. Immersion only D. Radiography Correct Answer: B. Pulse-echo
55. What does a strong backwall echo indicate? A. Internal defect B. Good coupling and sound transmission C. Probe failure D. High noise Correct Answer: B. Good coupling and sound transmission 56. Which material property most affects sound velocity? A. Color B. Elastic modulus C. Shape D. Surface roughness Correct Answer: B. Elastic modulus 57. What is the main limitation of UT? A. Cannot detect surface defects B. Requires skilled operator
C. Only works on plastics D. No electrical system needed Correct Answer: B. Requires skilled operator
58. What is coupling efficiency affected by? A. Probe color B. Surface roughness C. Display type D. Frequency only Correct Answer: B. Surface roughness 59. What is a common cause of false echoes? A. Proper calibration B. Geometry of test piece C. Good coupling D. Low frequency Correct Answer: B. Geometry of test piece 60. What is the purpose of reference reflectors? A. Increase gain B. Calibration and sensitivity setting C. Reduce attenuation D. Increase frequency
