CWB 2 Module 19 Questions and answers graded A+ 2023/2024

CWB 2 Module 19 QuestionsThe upper limit of human hearing is approximately: A) 20Hz B) 20kHz C) 20MHZ - correct answer B) 20kHz A typical frequency used for ultrasonic testing of welds is: A) 2.25MHZ B) 2.25kHz C) 2.25Hz - correct answer A) 2.25MHZ Do transverse waves in a solid travel faster or slower than longitudinal waves? - correct answer Slower True or False? The energy carried by a wave is proportional to the square of the amplitude. - correct answer True The decrease in energy of an ultrasonic wave as it travels through a material is known as: A) Amplitude B) Amplification C) Attenuation - correct answer C) Attenuation Piezoelectric crystals can: A) Change mechanical pulses into electrical pulses B) Change electrical pulses into mechanical pulses C) Both A and B - correct answer C) Both A and B The natural frequency of a given piezoelectric transducer is determined by: A) The amplitude of the voltage applied B) The transducer thickness C) Neither of the above. The frequency is set by the material being inspected and cannot be changed. - correct answer B) The transducer thickness Name one piezoelectric material: - correct answer Quartz and lead metaniobate In conventional ultrasonics the wave is injected into the specimen as a: A) Continuous wave that the natural frequency of the transducer. B) Short pulse containing several oscillations at the natural frequency - correct answer B) Short pulse containing several oscillations at the natural frequency Why is good acoustic contact between the transducer and the test specimen needed? - correct answer Ultrasonic waves of the frequency used in inspection do not travel far in air, so good coupling between the transducer and the specimen is needed True or false? A couplant is only needed if the surface is rough - correct answer False In A-scan display the vertical displacement of the trace is calibrated to represent: A) The amplitude of the reflected wave B) The size of the reflector C) Distance - correct answer A) The amplitude of the reflected wave In A-scan display the horizontal displacement of the trace is calibrated to represent: A) The amplitude of the reflected wave B) The size of the reflector C) Distance - correct answer C) Distance In what unit is the gain control (or attenuator) marked? - correct answer dB (decibels) Which type of display gives a cross-sectional view showing the length and depth of discontinuities? - correct answer B-Scan Give an example of a system where the entire specimen is immersed in water, which acts as the couplant. - correct answer On-line examination of plate defects such as laminations in a steel mill True or False? Acoustic emission relies on detecting very small amounts of mechanical energy released from such things as growing cracks or structural discontinuities under load. - correct answer True True or False? The plate and weld surface must always be ground smooth prior to ultrasonic examination. - correct answer False Why should most ultrasonic examinations of welds begin with a search of the place with a normal probe? - correct answer To identify plate defects such as laminations that could interfere with examination of the weld with an angle probe.