EMC RT Flashcards
The duty cycle of an x-ray tube is a measure of:
a) the maximum kilovoltage that can be applied to the tube.
b) the maximum filament current that can be applied.
c) the amount of time the tube must rest between exposures.
d) the amount of time required to warm up the tube before the first exposure of the day.
c) the amount of time the tube must rest between exposures.
The normal range of steel radiographed using IR-192 is:
a) 5mm to 25 mm
b) 25mm to 75mm
c) 5mm to 100mm
d) 45mm to 200mm
b) 25mm to 75mm
Of the following choices, indicate the most appropriate. In order to decrease exposure time, a
radiographer might:
a) use lead intensifying screens.
b) increase the focal film distance.
c) process at lower chemical temperatures.
d) use a copper filter at the window of the x-ray tube.
a) use lead intensifying screens.
Primary radiation which strikes a film holder or cassette through a thin portion of the specimen will
cause scattering into the shadows of the adjacent thicker portions producing an effect called:
a) radiation imaging.
b) spotting.
c) undercut.
d) unsharpness.
c) undercut.
Filters placed between the source of radiation and the specimen (or object) tend to reduce scatter
radiation undercutting the specimen by:
a) absorbing the longer wavelength components of the primary beam.
b) absorbing the shorter wavelength components of the primary beam.
c) absorbing backscatter radiation.
d) decreasing the intensity of the beam
a) absorbing the longer wavelength components of the primary beam.
A general rule often employed for determining the kilo-voltage to be used when x-raying a part is:
a) the kilovoltage should be as high as other factors will permit.
b) the kilovoltage should be as low as other factors will permit.
c) the kilovoltage is always a fixed value and cannot be changed.
d) the kilovoltage is not an important variable and can be changed over a wide range without
affecting the radiograph.
b) the kilovoltage should be as low as other factors will permit
The name of the defect which is most likely to occur at the junction of light and heavy sections is:
a) porosity
b) hot tear
c) blow hole
d) both a) and c)
b) hot tear
Oval or circular dark spots with smooth edges appearing on weld or casting radiographs would most
probably be indicative of:
a) burn through.
b) crater crack.
c) porosity.
d) lack of fusion.
c) porosity.
Where on a forged piece can you find a burst?
a) inside the piece
b) always on the surface of the piece
c) on the surface of the piece
d) answers a) and c) are correct
d) answers a) and c) are correct
Which defect results in damage to surfaces in contact, especially in a corrosive environment?
a) stress corrosion crack
b) embrittlement
c) fretting corrosion
d) intergranular corrosion
c) fretting corrosion
What must the direction of applied stress be to result in lamellar tearing?
a) Parallel to the rolling direction of the plate
b) Perpendicular to the rolling direction of the plate
c) 45N to the rolling direction of the plate
d) All of the above
b) Perpendicular to the rolling direction of the plate
Since rolling results in the flattening and elongation of a sheet of metal, what happens to a pocket of
gas in a metal sheet as a result of hot rolling?
a) It is still present and is the same size.
b) It is still present, and it grows.
c) It is still present but is larger in size.
d) None of the above answers.
d) None of the above answers.
Aluminum sand castings are subject to:
a) shrinkage cracks
b) surface porosity and cold shuts
c) micro-shrinkage
d) all of the above
d) all of the above
Hot tears generally originate:
a) internally or at the surface
b) from a large pore
c) from internal chaplets
d) from flat areas
a) internally or at the surface
Under-bead cracking occurs in the:
a) root pass of a weld
b) heat affected zone of a weld
c) second last layer of weld passes
d) crater at the end of a weld bead
b) heat affected zone of a weld
- In a shielded metal arc weld, entrapped gas pockets that are aligned and separated by a relatively
small distance is called:
a) piping porosity
b) linear porosity
c) pitting
d) straight porosity
b) linear porosity
Which of the following is not a discontinuity common to forged products?
a) Laps
b) Shrinkage
c) Bursts
d) Flakes
b) Shrinkage
Fine lines, likely to occur in groups caused by non-metallic impurities present in the original ingot and
extruded lengthwise are called:
a) stringers.
b) seams.
c) laminations.
d) laps.
a) stringers.
Is there a difference between a corrosion fatigue crack and intergranular corrosion in terms of the grain
of the metal?
a) No, as these two defects are transgranular
b) No, as these two defects are intergranular
c) Yes, as a corrosion fatigue crack is trans-granular and intergranular corrosion is intergranular
d) Yes, as a corrosion fatigue crack is intergranular and intergranular corrosion is transgranular
c) Yes, as a corrosion fatigue crack is trans-granular and intergranular corrosion is intergranular
