Theory

Question 1

The wave mode that has multiple or varying wave velocities is:

a. longitudinal waves
b. shear waves
c. transverse waves
d. Lamb waves

Answer 1

d. Lamb waves

Question 2

Which of the following would be considered application(s) of ultrasonic techniques?

a. Determination of a material’s elastic modulus.
b. Study of a material’s metallurgical structure.
c. Measurement of a material’s thickness.
d. All of the above.

Answer 2

d. All of the above.

Question 3

The only significant sound wave mode that travels through a liquid is a:

a. shear wave
b. longitudinal wave
c. surface wave
d. Rayleigh wave

Answer 3

b. longitudinal wave

Question 4

The acoustic impedance of a material is used to determine the:

a. angle of refraction at an interface
b attenuation within a material
c. relative amount of sound energy coupled through and reflected at an interface
d. beam spread within the material

Answer 4

c. relative amount of sound energy coupled through and reflected at an interface

Question 5

When angle beam contact testing a test piece, increasing the incident angle until the second critical angle is reached results in:

a. total reflection of a surface wave
b. 45 degree refraction of the shear wave
c. production of a surface wave
d. none of the above

Answer 5

c. production of a surface wave

Question 6

Acoustic energy propagates in different modes. Which of the following represent a mode?

a. A longitudinal wave
b. A shear wave
c. A surface wave
d. All of the above

Answer 6

d. All of the above

Question 7

The simple experiment where a stick in a glass of water appears disjointed at the water surface illustrates the phenomenon of:

a. reflection
b. magnification
c. refraction
d. diffraction

Answer 7

d. diffraction

Question 8

The crystal thickness and transducer frequency are related. The thinner the crystal:

a. the lower the frequency
b. the higher the frequency
c. there is no appreciable effect
d. none of the above

Answer 8

b. the higher the frequency

Question 9

The random distribution of crystallographic direction in alloys with large crystalline structures in factor in determining:

a. acoustic noise levels
b. selection of test frequency
c. scattering of sound
d. all of the above

Answer 9

d. all of the above

Question 10

The length of the zone adjacent to a transducer in which fluctuations in sound pressure occur is mostly affected by:

a. the frequency of the transducer
b. the diameter of the transducer
c. the length of the transducer cable
d. both a and b

Answer 10

d. both a and b

Question 11

The differences in signals received from identical reflectors at different materials distances from a transducer may be caused by:

a. material attenuation
b. beam divergence
c. near field effects
d. all of the above

Answer 11

d. all of the above

Question 12

In immersion testing, the near field effects of a transducer may be eliminated by:

a. increasing transducer frequency
b. using a larger diameter transducer
c. using appropriate water path
d. using a focused transducer

Answer 12

c. using appropriate water path

Question 13

Which of the following may result in a long narrow rod if the beam divergence results in a reflection from a side of the test piece before the sound wave reaches the back surface?

a. Multiple indications before the first back refection.
b. Indication from multiple surface reflections
c. Conversion from the longitudinal mode to shear mode.
d. loss from the surface indications

Answer 13

c. Conversion from the longitudinal mode to shear mode.

Question 14

Where does beam divergence occur?

a. near field
b. far field
c. at the crystal
d. none of the above

Answer 14

b. far field

Question 15

As frequency increases in ultrasonic testing, the angle of beam divergence if a given diameter crystal:

a. decreases
b. remains unchanged
c. increases
d. varies uniformly through each wavelength

Answer 15

a. decreases

Question 16

As the radius of curvature of a curved lens is increased, the focal length of the lens:

a. increases
b. decreases
c. remains the same
d. cannot be determined unless the frequency is known

Answer 16

a. increases

Question 17

When examining materials for planar flaws orientated parallel to the part surface, what testing method is most often used?

a. angle beam
b. through-transmission
c. straight beam
d. dual crystal

Answer 17

c. straight beam

Question 18

If a contact angle beam transducer produces a 45 degrees shear wave in steel, the angle produced by the same transducer in an aluminum specimen would be: (VS=0.323 cm/us; V=0.310 cm/us)

a. less than 45 degrees
b. greater than 45 degrees
c. 45 degrees
d. unknown: more information is required

Answer 18

a. less than 45 degrees

Question 19

Rayleigh waves are influenced most by defects located:

a. close to or on the surface
b. 1 wavelength below the surface
c. 3 wavelength below the surface
d. 6 wavelength below the surface

Answer 19

a. close to or on the surface

Question 20

The ultrasonic testing technique in which finger dampening is most effective in locating a discontinuity is the:

a. shear wave technique
b. Longitudinal wave technique
c. surface wave technique
d. compressional wave technique

Answer 20

c. surface wave technique

Question 21

Lamb waves can be used to detected:

a. laminar-type defects near the surface of a thin material
b. lack of fusion in the center of a thick weldment
c. internal voids in diffusional bonds
d. thickness changes in heavy plate material

Answer 21

a. laminar-type defects near the surface of a thin material

Question 22

The ratio of velocity of sound in water compared to that for aluminum of steel is approximately:

a. 1:8
b. 1:4
c. 1:3
d. 1:2

Answer 22

b. 1:4

Question 23

In an immersion test piece of steel or aluminum, the water distance appears on the display as a fairly wide space between the initial pulse and the front surface reflection because of:

a. reduced velocity of sound in water as compared to the test specimen
b. increased velocity if sound in water as compared to test specimen
c. temperature of the water
d. all of the above

Answer 23

a. reduced velocity of sound in water as compared to the test specimen

Question 24

Using the immersion method, a distance amplitute curve (DAC) for a 19mm (0.75 in.) diameter, 5 MHz transducer shows the high point of the DAC at the B/51 mm (2 in.) block. One day later, the high point
of the DAC for the same transducer is at the J/102 mm (4 in.) block. Assuming that the calibration has not changed, this would indicate the transducer:

a. is improving in resolution
b. is becoming defective
c. has the beam of a smaller transducer
d. both b and C

Answer 24

d. both b and C

Question 25

What law can be used to calculate the angle of refraction within a metal for both longitudinal and shear wave?

a. Poisson’s ratio law
b. Snell’s Law
c. Fresnel’s field law
d. Charles’ law

Answer 25

b. Snell’s Law

Question 26

At an interface between two different materials, an impedance difference results in:

a. reflection of the entire incident energy at the interface
b. absorption of sound
c. division of sound energy into transmitted and reflected modes
d. none of the above

Answer 26

c. division of sound energy into transmitted and reflected modes

Question 27

When using focused transducers, nonsymmetry in a propagated sound beam may by caused:

a. backing material variations
b. lens centering or misalignment
c. porosity in lenses
d. all of the above

Answer 27

d. all of the above

Question 28

During straight beam testing, test specimens with non-parallel front and back surfaces can cause:

a. partial or total loss of reflection
b. no loss in back reflection
c. a widened (broad) back reflection indication
d. a focused (narrow) back reflection

Answer 28

a. partial or total loss of reflection

Question 29

In B scan display, the length of a screen indication from a discontinuity is related to:

a. a discontinuity’s thickness as measured parallel to the ultrasonic beam
b. the discontinuity’s length in the direction of the transducer travel
c. both a and b
d. none of the above

Answer 29

b. the discontinuity’s length in the direction of the transducer travel

Question 30

Which circuit triggers the pulser and sweep circuits in the A-scan display?

a. receiver-amplifier
b. power supply
c. clock
d. damping

Answer 30

c. clock

Question 31

On a A-scan display, the “dead zone”, refers to:

a. the distance contained within the near field
b. the area outside the beam spread
c. the distance covered by the front surface pulse width and recovery time
d. the area between the near field and the far field

Answer 31

c. the distance covered by the front surface pulse width and recovery time

Question 32

On a A-scan display, what represents the intensity of a reflected beam?

a. echo pulse width
b. horizontal screen location
c. signal brightness
d. signal amplitude

Answer 32

d. signal amplitude

Question 33

Of the following scan types, which one can be used to produce a recording of flaw areas superimposed over a plan view of the test piece?

a. set the proper water path
b. set the proper transducer angle
c. set the proper index function
d. complete both a and b

Answer 33

d. complete both a and b

Question 34

In immersion testing in a small tank, manually operated manipulator is used to:

a. set the proper water path
b. set the proper transducer angle
c. set the proper index function
d. complete both a and b

Answer 34

d. complete both a and b

Question 35

In a straight (normal) beam contact testing, a reduction in the back reflection amplitude could indicate:

a. inadequate coupling
b. a flaw which is not normal to the beam
c. a near surface defect that cannot be resolved from the main bang (initial pulse)
d. all of the above

Answer 35

d. all of the above

Question 36

In an automatic scanning immersion unit, the bridge or carriage serves to:

a. support the manipulator and scanner tube and to move it about transversely and longitudinally
b. control the angular and transversely positioning of the scanner tube
c. control the vertical and angular positioning of the scanner tube
d. raise and lower the transducer

Answer 36

a. support the manipulator and scanner tube and to move it about transversely and longitudinally

Question 37

When adjusting the flaw locating rule for a shear wave weld inspection, the zero point on the rule must coincide with the:

a. sound beam exit point of the wedge
b. point directly over the flaw
c. wheel transducer
d. circular scanner

Answer 37

a. sound beam exit point of the wedge

Question 38

Compensation for the variation in echo height related to variations in discontinuity depth in the test material is known as

a. transfer
b. attenuation
c. distance amplitude correction
d. interpretation

Answer 38

c. distance amplitude correction

Question 39

Which of the following is a reference reflector that is not dependent on beam angle?

a. a flat bottom hole
b. a vee notch
c. a side drilled hole which is a parallel to the plate surface and perpendicular to the sound path
d. a disc-shaped laminar reflector

Answer 39

c. a side drilled hole which is a parallel to the plate surface and perpendicular to the sound path

Question 40

In figure 3, tranducer C is being used to check:

a. distance calibration
b. resolution
c. sensitivity calibration
d. verification of wedge angle

Answer 40

c. sensitivity calibration