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50 Cards in this Set
- Front
- Back
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Acoustic impedance is identified by the letter:
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Z
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What could influence the behavior of a transducer? |
Electrical construction
Material construction Mechanical construction |
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Which type of transducer can be used to scan wide areas when high sensitivity is not required?
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Paint brush transducer
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What type of set-up can provide information about both the size of the flaw and distance between the flaw and the transducer?
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Pulse echo
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The sound that emanates from a piezoelectric transducer originates:
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From most of the active surface
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The frequency marked on a transducer indicates:
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The center frequency at which the transducer operates
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Which type of calibration block is used to determine the resolution of angle beam transducers per requirements of AWS and AASHTO?
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An RC block
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Which of the following waves is able to follow a surface around a curve?
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A surface wave
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DAC stands for:
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Distance Amplitude Correction
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A decibel is:
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A logarithmic unit that describes a ratio of two measurements
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In order to have a reasonable chance at detecting a discontinuity, the reflective surface of the discontinuity must have a dimension that is at least as long as ________ wavelength.
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One-half
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Artificial flaws can be produced by using:
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Side drilled holes
Flat bottom holes EDM notches |
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A 6dB change in the measured ultrasonic signal strength indicates that the sound intensity changed by a factor of :
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Two
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Some transducers are specifically fabricated to be:
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Better transmitters
Better receivers Used in high temperature applications |
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Longitudinal waves are also called:
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Pressure waves
Compressional waves |
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What is the material called that is used to improve the transmission of ultrasonic sound energy from the transducer into the part?
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Couplant
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What part of the ultrasonic machine generates short, large-amplitude pulses of controlled energy?
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Pulser
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Which type of calibration block closely resembles the miniature angle-beam block and is used in a similar way?
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A DSC block
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Within a given material, the speed of sound:
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Is constant
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The total resistance that the cable presents to the electrical current passing through it is called:
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Impedance
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In angle-beam testing, when the geometry of the part is relatively uncomplicated and the orientation of a flaw is well known, the length of a crack can be determined by a technique known as:
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Tip diffraction
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Which of the following ultrasonic techniques require the probe to be held firmly against component?
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Contact inspection
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Mode conversion, occurs when a sound wave encounters an interface between materials of different acoustic impedance and:
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The incident angle is not normal to the interface
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What Greek letter is used to represent wavelength?
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lambda (λ)
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The terms used to describe a technique�s ability to locate flaws are:
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Sensitivity and resolution
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Ultrasound is generally defined as sound at frequency above the threshold of human hearing, which is?
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20,000 Hz
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Less damped transducers will exhibit:
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A narrow frequency range
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The ability to locate a small discontinuity is called:
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Sensitivity
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When a longitudinal wave encounters an interface between two material with different accoustic impedances, what occurs when the angle of incidence is 90 degrees?
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Reflection
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The sound energy or ultrasonic beam is more uniform in the:
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Far field zone
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Snell's Law describes the relationship between the sound velocity and:
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The refracted angle of the wave
The reflected angle of the wave |
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Contact transducers are used for direct contact inspections, and are generally:
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Hand manipulated
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Resolution generally increases:
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With an increase in transducer frequency
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As frequency increases, sound tends to:
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Scatter more from large or course grain structure
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Which type of test block is used to check horizontal linearity and the dB accuracy per requirements of AWS and AASHTO?
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Distance/Sensitivity block
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When sound travels through a medium:
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Its intensity diminishes with distance
It spreads perpendicular to the primary direction of wave travel Its speed remains constant |
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The combined effect of scattering and absorption is called:
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Attenuation
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Shear waves do not propagate in:
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Gases
Liquids |
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When an ultrasound wave passes through an interface between two materials at an oblique angle, and the materials have different indices of refraction, it produces:
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Reflected waves
Refracted waves |
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Couplant displaces the__________ and makes it possible to get more sound energy into the test specimen.
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Air
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Which of the following would make a good couplant?
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Water
Oil Glycerin |
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The a large acoustic impedance mismatch at an interface will result in:
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A high amount of reflected sound energy
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The first critical angle describes the condition where the:
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The angle of the refracted longitudinal wave is exactly 90o
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Which type of screen presentation displays the amount of received ultrasonic energy as a function of time?
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A-scan
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Which type of screen presentation displays a profile or cross-sectional view of the test specimen?
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B-scan
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Which type of screen presentation displays a plan-type view of the location and size of the test specimen features?
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C-scan
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Sound can propagate as:
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Longitudinal waves
Shear waves Surface waves |
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Why aren't real defects commonly used in calibration and reference standards?
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It is cost prohibitive to produce them
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What is used to establish a general level of consistency in measurements, and to help interpret and quantify the information contained in the received signal?
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Reference standards
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Which of the following waves is only able to travel through a thin section of material?
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A lamb wave
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