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36 Cards in this Set
- Front
- Back
What can cause irrelevant indications on the cathode ray tube? |
Contoured surfaces Edge Effects Surface Conditions All of the above |
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The number of complete waves which pass a given period of time (usually one second) is referred to as the |
Frequency of a wave motion |
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When testing a plate, increasing the frequency of an ultrasonic longitudinal wave will result in |
no change in its velocity |
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A term used in ultrasonics to express the rate at which sound waves pass through various substances is |
velocity |
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An advantage of using lithium sulfate in search units it that |
it is one of the most efficient receivers of ultrasonic energy |
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the velocity of surface waves is approximately _________ the velocity of shear waves in the same material |
Nine-tenths |
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The piezoeletric material in a search unit which vibrates to produce ultrasonic waves is called |
the transducer element or crystal |
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Ultrasonic waves transmitted into and received from the test material in the form of repetitive bursts of acoustic |
Pulse-echo testing |
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the cable that connects the ultrasonic instrument to the search unit is specifically designed so that one conductor is centered inside another. The technical name for the cable is |
Coaxial cable |
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The interference field near the face of a transducer is often referred to as the |
Fresnel Zone |
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A screen pattern containing a large number of low-lever indications (often referred to as "hash") could be caused by |
Coarse grained material |
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What type of ultrasonic examination uses wheel type units that eliminate the use of a tank? |
Immersion testing |
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The boundary between two different materials which are in contact with each other is called |
an interface |
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If the velocity of a longitudinal mode wave in a given homogeneous material is .625 cm/micro sec. at 1/2 inch below the surface, what is the velocity at 2 inch below the surface? |
The same as the velocity at 1/2 inch |
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The amount of beam divergence from a crystal is primarily dependent on the |
Frequency and crystal size |
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What vertical indication has reached the maximum signal height which can be displayed or viewed on the CRT of an ultrasonic instrument, the indication is said to have reached its |
Vertical Level |
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A B-scan display shows the relative |
Distance a discontinuity is from the transducer and its length in the direction of transducer travel |
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An amplitude type gate is necessary for all |
Automatic Examinations |
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The advantage of immersion testing includes which of the following? |
Inspection speed increased Ability to control and direct sound beams adaptability for automated scanning All of the above |
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The primary purpose of reference blocks is to |
Obtain a common reproducible signal |
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Which circuit generates a burst of energy which is applied to the sending transducer? |
Pulser |
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When performing a surface wave test, indications may result from |
Surface discontinuities oil on the surface dirt on the surface Alll of the above |
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Metal blocks which contain one or more drilled holes to simulate discontinuities are called |
Reference Blocks |
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What is the most common type of data display used for ultrasonic testing? |
An A-scan display |
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A term used to describe numerous small indications on the cathode ray tube screen resulting from test part structure, numerous small discontinuities, or both is often referred to as |
Hash |
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In a test where the transducer is not perpendicular to the inspection surface, the angle of incidence is equal to |
The angle of reflection |
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The product of the acoustic velocity of sound in a material and the density of the material is the factor that determines the amount of reflection or transmission of ultrasonic energy when it reaches an interface. This term is called |
Acoustic Impedance |
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Sound can be focused by means of special curved adapters located in front of the transducer element. These adapters are referred to as |
Acoustic Lenses |
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In immersion testing a wetting agent is added to the water to |
Help eliminate the formation of air bubbles |
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Which of the following materials of the same alloy is most likely to produce the greatest amount of sound attenuation over a given distance |
A coarse grained casting |
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A seperate time base line imposed on the viewing screen of some ultrasonic testing instruments that permits measurement of the distances is often referred to as |
a marker |
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In contact testing the entry surface indication is sometimes referred to as |
The initial pulse The "main band" or transmitter pulse Both A and B |
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The angle of incidence is |
Equal to the angle of reflection |
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Rough entry surface conditions can result in |
A loss of echo amplitude Increase in the width of the front surface echo Both A and B |
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Which component in an ultrasonic immersion system is used to adjust and maintain a known transducer angle? |
A manipulator |
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What must be done to evaluate discontinuities that are oriented at an angle to the entry surface that the |
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