METHODOS 2

Question 1

NR Review Questions
1. The highest intensity sources of thermal neutrons are:

a. Cf-252 isotopes.
b. accelerators.
c. nuclear fission reactors.
d. cosmic radiation.

Answer 1

c. nuclear fission reactors.

Question 2

2. Neutrons for fast-neutron radiography are obtainable from:

a. accelerators.
b. Co-60 or Ir-192.
c. moderated neutrons from reactors.
d. X-ray machines.

Answer 2

a. accelerators.

Question 3

3. A radioactive source used for NR is:

a. Cf-252.
b. Pu-239.
c. Co-60.
d. Cs-137.

Answer 3

a. Cf-252.

Question 4

4. The energy of the neutron is expressed in which of the following units of measurement?

a. Curies (becquerels).
b. Röntgen (coulombs per kilogram).
c. Rem (sieverts).
d. Electronvolts.

Answer 4

d. Electronvolts.

Question 5

5. A normally desirable feature of a thermal neutron beam for NR is:

a. background gamma radiation intensity.
b. relatively low fast-neutron intensity.
c. low angular divergence.
d. relatively high thermal neutron intensity.

Answer 5

b. relatively low fast-neutron intensity.

Question 6

6. A material that slows down neutrons is called:

a. a moderator.
b. an accumulator.
c. a limitor.
d. a collimator.

Answer 6

a. a moderator.

Question 7

7. The primary radiation mechanism for darkening radiographic film when the direct NR process is used with gadolinium screens is:

a. alpha particles.
b. electrons.
c. gamma rays.
d. light emission.

Answer 7

b. electrons.

Question 8

8. NR using the transfer method requires that the imaging screen must:

a. be placed behind the film.
b. be placed in front of the film.
c. be very thin.
d. become radioactive.

Answer 8

d. become radioactive.

Question 9

9. Which of the following NR converter foils cannot be used for transfer or indirect radiography?

a. Dysprosium.
b. Indium.
c. Gadolinium.
d. Gold.

Answer 9

c. Gadolinium.

Question 10

10. The most suitable films for producing neutron radiographs are:

a. industrial X-ray films.
b. red-sensitive films.
c. instant-type films.
d. emulsions that contain no silver halides.

Answer 10

a. industrial X-ray films.

Question 11

11. Materials that are exposed to thermal neutron beams:

a. must not be handled for at least 3 min after exposure has ceased.
b. must be stored in a lead-lined room.
c. should be monitored by means of a neutron counter.
d. may be radioactive after exposure to neutrons has ceased.

Answer 11

d. may be radioactive after exposure to neutrons has ceased.

Question 12

12. Lead is:

a. a good neutron shield.
b. corroded by neutron exposures.
c. a relatively poor neutron absorber.
d. an efficient conversion screen.

Answer 12

c. a relatively poor neutron absorber.

Question 13

13. If 2 mm (0.08 in.) of plastic attenuates a thermal neutron beam by a factor of 2, then 20 mm (0.8 in.) will attenuate it by approximately a factor of:

a. 10.
b. 20.
c. 200.
d. 1000.

Answer 13

d. 1000.

Question 14

14. Materials in common usage for moderation of fast neutron sources include:

a. aluminum, magnesium, and tin.
b. water, plastic, paraffin, and graphite.
c. neon, argon, and xenon.
d. tungsten, cesium, antimony, and columbium.

Answer 14

b. water, plastic, paraffin, and graphite.

Question 15

15. The main reason for using NR in place of X-radiography is:

a. a lower cost.
b. higher resolution.
c. the ability to image objects and materials not possible with X-rays.
d. it is a simpler radiographic procedure when required
than X-radiography.

Answer 15

c. the ability to image objects and materials not possible with X-rays.

Question 16

16. A photographic record produced by the passage of neutrons through a specimen onto a film is called:

a. a fluoroscopic image.
b. an isotopic reproduction.
c. a radiograph.
d. a track-etch photograph.

Answer 16

c. a radiograph.

Question 17

17. Many of the absorption differences between neutrons and X-rays indicate that the two techniques:

a. cause radiation problems.
b. complement each other.
c. can be used interchangeably.
d. can both be used to image hydrogenous materials equally well.

Answer 17

b. complement each other.

Question 18

18. The penetrating ability of a thermal neutron beam is governed by:

a. attenuating characteristics of the material being penetrated.
b. exposure time.
c. source-to-film distance.
d. thickness of the converter screen.

Answer 18

a. attenuating characteristics of the material being
penetrated.

Question 19

19. The transfer exposure method is used because:

a. it is not influenced by gamma radiation in the primary beam.
b. it produces greater radiographic sensitivity than direct exposure using gadolinium.
c. it is faster than the direct exposure method.
d. the screens used in this method emit only internal conversion electrons of about 70 keV.

Answer 19

a. it is not influenced by gamma radiation in the primary beam.

Question 20

20. Higher resolution can be achieved in direct NR by:

a. placing a lead intensifying screen between a gadolinium screen and the film.
b. increasing the length-to-diameter ratio of the collimation system.
c. increasing the exposure time.
d. increasing the distance between the object and the film cassette.

Answer 20

b. increasing the length-to-diameter ratio of the collimation system.

Question 21

21. The primary advantage of using a Cf-252 source for NR is its:

a. portability.
b. low cost per unit neutron flux compared to other neutron radiographic sources.
c. high resolution.
d. long useful life.

Answer 21

a. portability.

Question 22

22. Quality of the results from a neutron radiographic exposure is best determined by:

a. reference standards.
b. image quality indicators.
c. neutron flux measurement.
d. densitometer readings.

Answer 22

b. image quality indicators.

Question 23

23. The radiographic image of apparent discontinuities in the imaging screens can be separated from actual discontinuities in a part being radiographed by:

a. comparing a neutron radiograph of the parts to a blank neutron radiograph of the same imaging screen with no parts in place.
b. producing a photographic copy of the original neutron radiograph using X-ray duplicating film.
c. increasing the exposure time of the radiograph.
d. decreasing the temperature of the developer solution.

Answer 23

a. comparing a neutron radiograph of the parts to a blank neutron radiograph of the same imaging screen with no parts in place.

Question 24

24. For inspection of radioactive objects or those that emit gamma radiation when bombarded with neutrons, a preferable detection technique is the:

a. direct exposure technique.
b. transfer technique.
c. isotopic reproduction technique.
d. electrostatic-belt generator technique.

Answer 24

b. transfer technique.

Question 25

25. NR is an excellent tool for determining:

a. the coating thickness of aluminum oxide on anodized aluminum.
b. the size of voids in thick steel castings.
c. the integrity of thin plastic material within a steel housing.
d. tungsten inclusions in gas tungsten arc welding welds.

Answer 25

c. the integrity of thin plastic material within a steel housing.

Question 26

26. NR extends radiographic capability for detecting cracks in small cylinders of:

a. aluminum.
b. iron.
c. magnesium.
d. plutonium.

Answer 26

d. plutonium.

Question 27

27. Which of the following is a preferred application of NR?

a. Detection of tungsten inclusions in titanium ingots.
b. Detecting the presence of water in the cells of stainless steel honeycomb.
c. Detecting slag inclusions in structural steel welds.
d. Determination of the depth of seating of a projectile in a metallic case.

Answer 27

b. Detecting the presence of water in the cells of stainless steel honeycomb.

Question 28

28. Common sources of neutrons for NR are:

a. electron linear accelerators.
b. isotopes of cobalt (e.g., Co-60).
c. nuclear reactors.
d. betatrons.

Answer 28

c. nuclear reactors.

Question 29

RT Review Questions
1. The penetrating ability of an X-ray beam is governed by:

a. kilovoltage or wavelength (energy).
b. time.
c. milliamperage.
d. source-to-film distance.

Answer 29

a. kilovoltage or wavelength (energy).

Question 30

2. Two X-ray machines operating at the same nominal kilovoltage and milliamperage settings:

a. will produce the same intensities and energies of radiation.
b. will produce the same intensities but may produce different energies of radiation.
c. will produce the same energies but may produce different intensities of radiation.
d. may give not only different intensities but also different energies of radiation.

Answer 30

d. may give not only different intensities but also different energies of radiation.

Question 31

3. Short wavelength electromagnetic radiation produced during the disintegration of nuclei of radioactive substances is called:

a. X-radiation.
b. gamma radiation.
c. scatter radiation.
d. beta radiation.

Answer 31

b. gamma radiation.

Question 32

4. Almost all gamma radiography is performed with:

a. natural isotopes.
b. artificially produced isotopes.
c. radium.
d. Co-60.

Answer 32

b. artificially produced isotopes.

Question 33

5. The energy of gamma rays is expressed by which of the following units of measurement?

a. Curie (gigabecquerel).
b. Röntgen (coulomb per kilogram).
c. Half-life.
d. Kiloelectronvolts (keV) or megaelectronvolts (MeV).

Answer 33

d. Kiloelectronvolts (keV) or megaelectronvolts (MeV).

Question 34

6. Of the following, the source providing the most penetrating radiation is:

a. Co-60.
b. 220 kVp X-ray tube.
c. 15 MeV betatron.
d. electrons from Ir-192.

Answer 34

c. 15 MeV betatron.

Question 35

7. The difference between the densities of two areas of a radiograph is called:

a. radiographic contrast.
b. subject contrast.
c. film contrast.
d. definition.

Answer 35

a. radiographic contrast.

Question 36

8. The fact that gases, when bombarded by radiation, ionize and become electrical conductors makes them useful in:

a. X-ray transformers.
b. fluoroscopes.
c. masks.
d. radiation detection equipment.

Answer 36

d. radiation detection equipment.

Question 37

9. The reason exposure time must be increased by a factor of four when the source-to-film distance is doubled is that the:

a. intensity of radiation decreases at an exponential rate when the source-to-film distance is increased.
b. energy of radiation is inversely proportional to the square root of the distance from the source to the
film.
c. intensity of radiation is inversely proportional to the square of the distance from the source to the film.
d. scattered radiation effect is greater as the source-to-film distance increases.

Answer 37

c. intensity of radiation is inversely proportional to the square of the distance from the source to the film.

Question 38

10. The most important factor in X-ray absorption of a specimen is:

a. the thickness of the specimen.
b. the density of the specimen.
c. Young’s modulus of the material.
d. the atomic number of the material.

Answer 38

d. the atomic number of the material.

Question 39

11. The maximum permissible dose per calendar year is 5 rem (0.05 Sv) for:

a. extremities.
b. skin.
c. whole body (total effective dose equivalent).
d. a fetus from occupational exposure of a declared pregnant woman.

Answer 39

c. whole body (total effective dose equivalent).

Question 40

12. Exposure to small doses of X-rays or gamma rays:

a. has a cumulative effect that must be considered when monitoring for maximum permissible dose.
b. is beneficial because it serves to build an immunity in humans to radiation poisoning.
c. will have no effect on human beings.
d. will have only a short-term effect on human tissues.

Answer 40

a. has a cumulative effect that must be considered when monitoring for maximum permissible dose.

Question 41

13. Which of the following technique variables is most commonly used to adjust subject contrast?

a. Source-to-film distance.
b. Milliamperage.
c. Kilovoltage.
d. Focal spot size.

Answer 41

c. Kilovoltage.

Question 42

14. A basic difference between a radiograph and a fluoroscopic image is:

a. the fluoroscopic image is more sensitive.
b. the fluoroscopic image is positive whereas the radiographic image is negative.
c. the fluoroscopic image is brighter.
d. there is no basic difference between the two.

Answer 42

b. the fluoroscopic image is positive whereas the
radiographic image is negative.

Question 43

15. Thin sheets of lead foil in intimate contact with X-ray film during exposure increase film density because they:

a. fluoresce and emit visible light, which helps expose the film.
b. absorb the scattered radiation.
c. prevent backscattered radiation from fogging the film.
d. emit electrons when exposed to X- and gamma radiation, which helps to darken the film.

Answer 43

d. emit electrons when exposed to X- and gamma radiation, which helps to darken the film.

Question 44

16. When viewing a radiograph, an image of the back of the cassette superimposed on the image of the specimen is noted. This is most likely due to:

a. undercut.
b. overexposure.
c. X-ray intensity being too high.
d. backscatter radiation.

Answer 44

d. backscatter radiation.

Question 45

17. An image quality indicator (IQI) is used to measure the:

a. size of discontinuities in a part.
b. density of the film.
c. quality of the radiographic technique.
d. amount of radiation that penetrates the test object.

Answer 45

c. quality of the radiographic technique.

Question 46

18. In film radiography, IQIs are usually placed:

a. between the intensifying screen and the film.
b. on the source side of the test object.
c. on the film side of the test object.
d. between the operator and the radiation source.

Answer 46

b. on the source side of the test object.

Question 47

19. At voltages above 400 kV, the use of lead to provide protection may present serious structural problems. If
    this should be the case, which of the following materials would most likely be used as a substitute?

a. Concrete.
b. Aluminum.
c. Steel.
d. Boron.

Answer 47

a. Concrete.

Question 48

20. A distinctive characteristic of megavolt radiography is that it:

a. results in comparatively high subject contrast.
b. results in comparatively high radiographic contrast.
c. is applicable to comparatively thick or highly absorbing specimens.
d. is utilized for stainless steels only.

Answer 48

c. is applicable to comparatively thick or highly absorbing specimens.

Question 49

21. Given the radiographic equivalency factors of 1.4 for Inconel TM and 1.0 for 304 stainless steel, what is the approximate equivalent thickness of Inconel TM to produce the same exposure as a 3.8 mm (0.15 in.) thickness of 304 stainless steel?

a. 3 mm (0.11 in.)
b. 9 mm (0.35 in.)
c. 18 mm (0.7 in.)
d. 36 mm (1.4 in.)

Answer 49

a. 3 mm (0.11 in.)

Question 50

22. The fact that each solid crystalline substance produces its own characteristic X-ray pattern is the basis for:

a. xeroradiography.
b. X-ray diffraction testing.
c. fluoroscopic testing.
d. polymorphic testing.

Answer 50

b. X-ray diffraction testing.

Question 51

23. When inspecting a light metal casting by fluoroscopy, which of the following discontinuities would most likely be detected?

a. Copper shrinkage.
b. Microshrinkage.
c. Shrinkage.
d. Fine cracks.

Answer 51

c. Shrinkage.

Question 52

24. For testing a 25 mm (1 in.) steel plate 305 mm (12 in.) square for laminar discontinuities, which of the following
    would be most effective?

a. 3.7 TBq (100 Ci) of Ir-192.
b. 925 GBq (25 Ci) of Co-60.
c. 250 kVp X-ray machine.
d. An ultrasonic device.

Answer 52

d. An ultrasonic device.

Question 53

25. A critical weld was made with a double vee-groove. Among those listed, which radiographic technique would provide coverage with the greatest probability for detecting the most serious discontinuities?

a. A single exposure centered on the weld and perpendicular to the principal surface of the plate.
b. Two exposures aligned with the vee-groove, focus ±30° off perpendicular.
c. Two exposures, perpendicular to the plate, offset by the width of the weld bead.
d. A single exposure centered on the weld with two films aligned ±30° off perpendicular to the principal surface of the plate.

Answer 53

b. Two exposures aligned with the vee-groove, focus ±30° off perpendicular.

Question 54

26. A fuse assembly is radiographed so that measurements can be made on the film to determine a minimum internal clearance dimension. What should be factored into the dimension taken from the film?

a. Projection magnification.
b. Film latitude.
c. Slope of the characteristic curve.
d. IQI alignment.

Answer 54

a. Projection magnification.

Question 55

27. Miniature electronic components are to be radiographically inspected to reveal broken copper wire leads of 0.008 in. (0.2 mm) diameter. Which of the following IQIs would be most effective to use in establishing a reliable technique?

a. A series of steel plaque-type IQIs ranging in thickness from 0.1 mm (0.005 in.) to 0.4 mm (0.015 in.), containing 1T, 2T, and 4T holes.
b. A plastic block with the radiographic thickness equivalent of the test objects, containing precision drilled holes ranging from 0.1 mm (0.005 in.) to 0.4 mm (0.015 in.) diameter.
c. A plastic block with the radiographic thickness equivalent of the test objects, containing copper wires ranging from 0.1 mm (0.005 in.) to 0.4 mm (0.015 in.)
diameter.
d. A series of copper shims ranging in thickness from 0.1 mm (0.005 in.) to 0.4 mm (0.015 in.), containing 1/2T and 1T holes.

Answer 55

c. A plastic block with the radiographic thickness equivalent of the test objects, containing copper wires ranging from 0.1 mm (0.005 in.) to 0.4 mm (0.015 in.)
diameter.

Question 56

Thermal/Infrared Testing Review Questions
1. Thermal resistance is:

a. analogous to electrical current.
b. a material’s impedance to heat flow.
c. proportional to the fourth power of emissivity.
d. proportional to the rate of heat flow.

Answer 56

b. a material’s impedance to heat flow.

Question 57

2. Conductive heat transfer can take place:

a. across a vacuum.
b. from a hair dryer blowing on an object.
c. between a heat lamp and a distant object.
d. between dissimilar metals in contact with each other.

Answer 57

d. between dissimilar metals in contact with each other.

Question 58

3. The infrared/thermal energy emitted from a target surface:

a. occurs only in a vacuum.
b. is inversely proportional to surface emissivity.
c. is proportional to the fourth power of the absolute surface temperature.
d. is totally absorbed by water vapor in the air.

Answer 58

c. is proportional to the fourth power of the absolute surface temperature.

Question 59

4. Thermal radiation reaching the surface of a thermally opaque object will only be:

a. absorbed by the surface.
b. absorbed and reflected by the surface.
c. reflected by the surface.
d. transmitted and absorbed by the surface.

Answer 59

b. absorbed and reflected by the surface.

Question 60

5. The following spectral band is included in the infrared spectrum:

a. 0.1 to 5.5 μm
b. 0.3 to 10.6 μm
c. 0.4 to 20 μm
d. 0.75 to 100 μm

Answer 60

d. 0.75 to 100 μm

Question 61

6. As a surface cools, the peak of its radiated infrared energy:

a. shifts to longer wavelengths.
b. shifts to shorter wavelengths.
c. remains constant if emissivity remains constant.
d. remains constant even if emissivity varies.

Answer 61

a. shifts to longer wavelengths.

Question 62

7. A graybody surface with an emissivity of 0.04 would be:

a. transparent to infrared radiation.
b. a fairly good emitter.
c. almost a perfect reflector.
d. almost a perfect emitter.

Answer 62

c. almost a perfect reflector.

Question 63

8. If a surface has an emissivity of 0.35 and a reflectivity of 0.45, its transmissivity would be:

a. impossible to determine without additional information.
b. 0.80.
c. 0.10.
d. 0.20.

Answer 63

d. 0.20.

Question 64

9. The spectral band in which glass transmits infrared radiation most efficiently is the:

a. 3 to 6 μm region.
b. 2 to 3 μm region.
c. 6 to 9 μm region.
d. 9 to 11 μm region.

Answer 64

b. 2 to 3 μm region.

Question 65

10. Infrared thermal detectors:

a. have a broad, flat spectral response.
b. have much faster response times than photon detectors.
c. usually require cooling to operate properly.
d. have much greater sensitivity than photon detectors.

Answer 65

a. have a broad, flat spectral response.

Question 66

11. A diffuse reflecting surface is:

a. a polished surface that reflects incoming energy at a complementary angle.
b. a surface that scatters reflected energy in many directions.
c. also called a specular reflecting surface.
d. highly transparent to infrared radiation.

Answer 66

b. a surface that scatters reflected energy in many directions.

Question 67

12. The minimum resolvable temperature difference is a subjective measurement that depends on:

a. the infrared imaging system’s spatial resolution only.
b. the infrared imaging system’s measurement resolution only.
c. the infrared imaging system’s thermal sensitivity and spatial resolution.
d. the infrared imaging system’s minimum spot size.

Answer 67

c. the infrared imaging system’s thermal sensitivity and spatial resolution.

Question 68

13. The spatial resolution of an instrument is related to the:

a. thermal resolution.
b. spectral bandwidth.
c. system responsivity.
d. instantaneous field of view and the working distance.

Answer 68

d. instantaneous field of view and the working distance.

Question 69

14. The noise equivalent temperature difference (NETD) of a thermal infrared imager tends to:

a. improve as the target temperature increases.
b. degrade as the target temperature increases.
c. remain constant regardless of the target temperature.
d. improve with increasing working distance.

Answer 69

a. improve as the target temperature increases.

Question 70

15. The 3 to 5 μm spectral region is well suited for:

a. inspection using a microbolometer.
b. measuring targets at extremely long working distances.
c. measuring targets warmer than 200 °C (392 °F).
d. operating at near ambient temperatures.

Answer 70

c. measuring targets warmer than 200 °C (392 °F).

Question 71

16. When measuring the temperature of glass while using a mid-wave (3 to 5 μm) infrared imaging system, which of
    the following steps is necessary?

a. Use a 3.2 μm low-pass filter.
b. Use a 5 μm high-pass filter.
c. No filter is necessary if using the same emissivity setting used with long-wave imaging systems.
d. Use a 3.9 μm bandpass filter.

Answer 71

d. Use a 3.9 μm bandpass filter.

Question 72

17. A line scanner is best used for applications:

a. requiring online real-time process monitoring and control of a linear thermal process.
b. where the material is stationary.
c. where the process speed is no greater than 3 m/s.
d. where the maximum temperature of the material is 300 °C (572 °F).

Answer 72

a. requiring online real-time process monitoring and control of a linear thermal process.

Question 73

18. Most infrared focal plane array imagers:

a. use more costly optics than scanning radiometers.
b. offer better spatial resolution than scanning radiometers.
c. offer better thermal resolution than scanning radiometers.
d. offer less diagnostics features than scanning radiometers.

Answer 73

b. offer better spatial resolution than scanning radiometers.

Question 74

19. When measuring the temperature of a nongray target:

a. the viewing angle is not critical.
b. always assume a uniform emissivity.
c. varying surface temperature differences can be ignored.
d. errors may occur when using a variety of instruments.

Answer 74

d. errors may occur when using a variety of instruments.

Question 75

20. Thermal diffusivity is:

a. high for metals and low for porous materials.
b. the same for all metals.
c. low for metals and high for porous materials.
d. the same for all porous materials.

Answer 75

a. high for metals and low for porous materials.

Question 76

21. The term used to describe a material’s surface temperature response to a given energy input is called:

a. diffuse reflectivity.
b. thermal conductance.
c. thermal effusivity.
d. spectral transmittance.

Answer 76

c. thermal effusivity.

Question 77

UT Review Questions
1. Ultrasonic waves propagate through test materials in the form of:

a. electromagnetic waves.
b. low-voltage electric fields.
c. discontinuous radio waves.
d. mechanical vibrations.

Answer 77

d. mechanical vibrations.

Question 78

2. When an ultrasonic beam passes through the interface of two dissimilar materials at an angle, a new angle of sound
   travel takes place in the second material due to:

a. refraction.
b. attenuation.
c. rarefaction.
d. compression.

Answer 78

a. refraction.

Question 79

3. The gradual loss of energy as ultrasonic vibrations travel through material is referred to as:

a. reflection.
b. refraction.
c. compression.
d. attenuation.

Answer 79

d. attenuation.

Question 80

4. Ultrasonic velocities are different for different materials.
   These differences are primarily caused by differences in the materials’:

a. frequency and wavelength.
b. thickness and travel time.
c. elasticity and density.
d. chemistry and permeability.

Answer 80

c. elasticity and density.

Question 81

5. Ultrasonic energy for immersion testing is transmitted to the test object as a compressional wave because:

a. compressional waves travel faster and will therefore reduce the distance of the interface signal.
b. liquids will only sustain compressional waves.
c. compressional waves are used with immersion testing only.
d. the higher intensity of compressional waves is necessary to overcome high attenuation in liquids.

Answer 81

b. liquids will only sustain compressional waves.

Question 82

6. When inspecting coarse-grained materials, which of the following frequencies will generate a sound wave that will be most easily scattered by the grain structure?

a. 1.0 MHz
b. 2.25 MHz
c. 5 MHz
d. 10 MHz

Answer 82

d. 10 MHz

Question 83

7. In general, shear waves are more sensitive to small discontinuities than longitudinal waves for a given
   frequency and in a given material because:

a. the wavelength of shear waves is shorter than the wavelength of longitudinal waves.
b. shear waves are not as easily dispersed in the material.
c. the direction of particle vibration for shear waves is more sensitive to discontinuities.
d. the wavelength of shear waves is longer than the wavelength of longitudinal waves.

Answer 83

a. the wavelength of shear waves is shorter than the wavelength of longitudinal waves.

Question 84

8. The ability of transducers to detect echoes from small discontinuities is a definition of:

a. resolution.
b. sensitivity.
c. definition.
d. gain.

Answer 84

b. sensitivity.

Question 85

9. Which of the following will create a resonance condition
   in a specimen?

a. Continuous longitudinal waves.
b. Pulsed longitudinal waves.
c. Pulsed shear waves.
d. Continuous shear waves.

Answer 85

a. Continuous longitudinal waves.

Question 86

10. The display on most basic pulse-echo ultrasonic
    instruments consists of:

a. automatic read-out equipment.
b. an A-scan presentation.
c. a B-scan presentation.
d. a C-scan presentation.

Answer 86

b. an A-scan presentation.

Question 87

11. In a basic pulse-echo ultrasonic instrument, the
    component that produces the voltage that activates the
    search unit is called:

a. an amplifier.
b. a receiver.
c. a pulser.
d. a synchronizer.

Answer 87

c. a pulser.

Question 88

12. The primary purpose of reference blocks is to:

a. aid the operator in obtaining maximum back reflections.
b. obtain the greatest sensitivity possible from an instrument.
c. provide a known reflecting area in calibrating an instrument.
d. establish the size and orientation of a discontinuity.

Answer 88

c. provide a known reflecting area in calibrating an instrument.

Question 89

13. The general use of distance-amplitude correction is to compensate for:

a. attenuation, distance, and beam spread.
b. amplitude of noise signals.
c. velocity changes.
d. vertical nonlinearity in the ultrasonic instrument.

Answer 89

a. attenuation, distance, and beam spread.

Question 90

14. In area-amplitude ultrasonic standard test blocks, the flat bottom holes in the blocks are:

a. all the same diameter.
b. different in diameter, increasing in size of 1/64 in. (0.0156 in.) increments from the No. 1 block to the No. 8 block.
c. largest in the No. 1 block and smallest in the No. 8
block.
d. drilled to different depths from the front surface of the test block.

Answer 90

b. different in diameter, increasing in size of 1/64 in. (0.0156 in.) increments from the No. 1 block to the No. 8 block

Question 91

15. Which of the following factors has the least influence on
    the amount of energy reflected from a discontinuity?

a. Size of the discontinuity.
b. Orientation of the discontinuity.
c. Discontinuity type.
d. Test frequency.

Answer 91

d. Test frequency.

Question 92

16. The ability to locate discontinuities that are close together within the material is called:

a. resolution.
b. sensitivity.
c. effectiveness.
d. phase delay.

Answer 92

a. resolution.

Question 93

17. Lack of parallelism between the entry surface and the
    back surface:

a. may result in a screen pattern that does not contain
back reflection indications.
b. makes it difficult to locate discontinuities that lie
parallel to the entry surface.
c. usually indicates a porous condition existing in the metal.
d. will decrease the penetrating power of the test.

Answer 93

a. may result in a screen pattern that does not contain
back reflection indications.

Question 94

18. Significant errors in ultrasonic thickness measurement
    can occur if:

a. test velocity is kept constant.
b. the velocity of propagation deviates substantially
from an assumed constant value for a given material.
c. water is used as a couplant between the transducer
and the part being measured.
d. longitudinal waves are used.

Answer 94

b. the velocity of propagation deviates substantially
from an assumed constant value for a given material.

Question 95

19. In contact testing, shear waves can be induced in the test material by:

a. placing an X-cut quartz crystal directly on the surface
of the material and coupling through a film of oil.
b. using two transducers on opposite sides of the test
specimen.
c. using an angle-beam transducer with the transducer
mounted on a plastic wedge so that sound enters the
part at an angle.
d. placing a spherical acoustic lens on the face of the
transducer.

Answer 95

c. using an angle-beam transducer with the transducer
mounted on a plastic wedge so that sound enters the
part at an angle.

Question 96

20. The most commonly used method of producing shear
    waves in a test part when inspecting by the immersion
    method is by:

a. transmitting longitudinal waves into a part in a
direction perpendicular to its front surface.
b. using two crystals vibrating at different frequencies.
c. using a low-frequency transducer.
d. angulating the transducer to the proper angle with
respect to the entry surface of the test part.

Answer 96

d. angulating the transducer to the proper angle with
respect to the entry surface of the test part.

Question 97

21. In immersion testing, proof that the search unit is normal (perpendicular) to a flat entry surface is indicated by:

a. maximum reflection amplitude from the entry surface.
b. elimination of water multiples.
c. maximum reflection amplitude from the back surface.
d. maximum amplitude of the initial pulse.

Answer 97

a. maximum reflection amplitude from the entry surface.

Question 98

22. In immersion testing, the water distance between the
    search unit and the test piece:

a. should be as small as possible.
b. will have no effect on the test.
c. should be the same as the water distance used during
calibration.
d. should be as great as possible.

Answer 98

c. should be the same as the water distance used during
calibration.

Question 99

23. Generally, the best UT technique for detecting discontinuities oriented along the fusion zone in a welded
    plate is:

a. an angle-beam contact method employing surface
waves.
b. an immersion test using surface waves.
c. a resonance technique.
d. an angle-beam method using shear waves.

Answer 99

d. an angle-beam method using shear waves.

Question 100

24. Thin sheet may be inspected for laminar discontinuities
    with the ultrasonic wave directed normal (perpendicular)
    to the surface by observing:

a. the amplitude of the front surface reflection.
b. the multiple reflection pattern.
c. the amplitude of the initial pulse.
d. signals that “walk” or move along the time base as the
transducer is scanned over the sheet.

Answer 100

b. the multiple reflection pattern.

Question 101

25. Ultrasonic inspection of castings is occasionally
    impractical because of:

a. extremely small grain structure typical in castings.
b. coarse grain structure.
c. uniform flow lines.
d. random orientation of discontinuities.

Answer 101

b. coarse grain structure.

Question 102

26. Angle-beam testing of plate will often miss:

a. cracks that are perpendicular to the sound wave.
b. inclusions that are randomly oriented.
c. laminations that are parallel to the front surface.
d. a series of small discontinuities.

Answer 102

c. laminations that are parallel to the front surface.

Question 103

27. In addition to a weld area being inspected by the angle beam technique, which additional test is typically performed to detect laminations in the base metal?

a. Through-transmission testing.
b. Guided wave testing.
c. Straight-beam testing.
d. Surface-wave testing.

Answer 103

c. Straight-beam testing.

Question 104

28. An ultrasonic test using a straight-beam contact search
    unit is being conducted through the thickness of a flat
    part, such as plate. This test should detect:

a. laminar-type discontinuities with major dimensions
parallel to the plane of the rolled surface.
b. transverse-type discontinuities with major
dimensions at right angles to the plane of the rolled
surface.
c. radial discontinuities with major dimensions along
the length but radially oriented to the rolled surface.
d. rounded discontinuities at the edges of the rolled
plate.

Answer 104

a. laminar-type discontinuities with major dimensions
parallel to the plane of the rolled surface.

Question 105

29. UT techniques are useful in testing laminate and sandwich construction test objects for:

a. paint thickness.
b. bond integrity.
c. leakage.
d. surface roughness.

Answer 105

b. bond integrity.

Question 106

30. UT techniques are frequently used in online automatic
    process control applications to measure and control:

a. moisture content in materials.
b. surface roughness of turbine blade castings.
c. the thickness of cold-rolled strips, sheets, and plates.
d. chemical activity in chemical etching processes.

Answer 106

c. the thickness of cold-rolled strips, sheets, and plates.

Question 107

31. Which of the following statements about field inspection
    applications of UT is true?

a. Manual and automatic systems can be used for field
inspections.
b. Because the equipment is large and bulky, field
inspections are difficult, at best.
c. Aircraft and other field maintenance inspections
usually require three persons: one to manipulate the
transducer, one to monitor the instrument, and one
to record results.
d. Digital displays must be used for outdoor inspection
because of the limited brightness of screen displays.

Answer 107

a. Manual and automatic systems can be used for field
inspections.

Question 108

32. Which of the following waves is able to follow a surface
    around a curve?

a. Longitudinal wave.
b. Shear wave.
c. Surface wave.
d. Lamb wave.

Answer 108

d. Lamb wave.

Question 109

Visual Testing Review Questions
1. VT could be best described as:

a. detection of near surface anomalies and various color variations.
b. optical detection of surface anomalies and checking
conformance to specification.
c. evaluation of metallurgical conditions via electronic
microscope.
d. examination for a wide variety of discontinuities open
to or just below the surface.

Answer 109

b. optical detection of surface anomalies and checking
conformance to specification.

Question 110

2. What element of the eye is analogous to a digital camera,
   converting a light pattern into electronic signals?

a. Eye muscle.
b. Iris.
c. Lens.
d. Retina.

Answer 110

d. Retina.

Question 111

3. Illumination varies inversely as the square of the distance
   between the source and the point on the surface
   increases. What is this law called?

a. Inverse square law.
b. Cosine law.
c. Generation of light law.
d. Lambert’s law.

Answer 111

a. Inverse square law.

Question 112

4. When measuring surface roughness, Ra is defined as what?

a. Average distance between the highest and lowest
points.
b. Average waviness from crest to trough.
c. Average distance of the profile to the mean line.
d. Parameter of friction between contact surfaces.

Answer 112

c. Average distance of the profile to the mean line.

Question 113

5. What is the minimum luminance recommended by the
   Illuminating Engineering Society (IES) for task lighting
   with medium contrast and small size detection desired?

a. 100 lx
b. 200 lx
c. 500 lx
d. 2000 lx

Answer 113

c. 500 lx

Question 114

6. What is the direction of view called in a borescope or
   videoscope when viewing 45° off the straight-ahead
   direction of the probe?

a. Forward slant.
b. Forward oblique.
c. Forespective.
d. Angulated.

Answer 114

b. Forward oblique.

Question 115

7. How many bundles are there in a fiber-optic borescope
   and what are they called?

a. One; monochromatic bundle.
b. Two; light guide and image guide.
c. Two; light guide and CCD cable bundle.
d. Three; light guide, image guide, and fiber sheath.

Answer 115

b. Two; light guide and image guide.

Question 116

8. What is a commonly evident surface discontinuity visible
   to the unaided eye following forming?

a. Forging bursts at the center of the billet.
b. Laminations at end preparations of plate for welding.
c. Edge breaks in temper-rolled sheets of steel.
d. Segregation between pours.

Answer 116

c. Edge breaks in temper-rolled sheets of steel.

Question 117

9. What type of cracking occurs at the termination point of a
   weld made by tungsten inert gas welding?

a. Crater crack.
b. Hot tearing.
c. Cold cracking.
d. Hot cracking.

Answer 117

a. Crater crack.

Question 118

10. What is pillowing corrosion on aircraft lap joints, typically on aircraft skins, usually attributed to?

a. Misalignment corrosion of fasteners used to attach
the skins to the airframe.
b. Stretching of the skins beyond their yield points over
time.
c. Expansion of corrosion products under the skins.
d. Twisting of the airframe during tight turns and similar
maneuvers.

Answer 118

c. Expansion of corrosion products under the skins.

Question 119

11. When inspecting welds for discontinuities located by VT,
    which of the following discontinuities is usually judged
    the least detrimental, depending on its depth?

a. Undercut.
b. Cracks.
c. Lack of fusion.
d. Incomplete penetration.

Answer 119

a. Undercut.

Question 120

12. How can the heat-affected zone (HAZ) of carbon steel
    welds be made visible?

a. Etchants to enhance the visibility of the microstructure.
b. High-frequency ultrasonic microscopic means.
c. Color-contrast penetrating liquids.
d. Arrays of temperature-sensitive markings.

Answer 120

a. Etchants to enhance the visibility of the microstructure.

Question 121

13. Reflectance is a measure of:

a. the reactance of a coating.
b. the mirror-like reflectance of a surface.
c. the amount of artificial light at the inspection surface.
d. the flatness of a finish coating.

Answer 121

b. the mirror-like reflectance of a surface.

Question 122

14. A datum:

a. is a theoretical point identified on the blueprint.
b. is a theoretical point, axis, or plane, derived from
actual part features.
c. is a feature controlled by two separate datums.
d. has form only in terms of itself.

Answer 122

b. is a theoretical point, axis, or plane, derived from
actual part features.

Question 123

15. Color order systems describe color by:

a. value and brightness saturation.
b. primary and secondary colors.
c. value, hue, and saturation.
d. value of the primary color constituents.

Answer 123

c. value, hue, and saturation.

Question 124

16. A concave mirror can be helpful by:

a. focusing the image viewed.
b. diverging and optically reversing small images.
c. converging and optically reversed small images.
d. increasing the light returned to the inspector.

Answer 124

b. diverging and optically reversing small images.