EMC ET Flashcards
Discontinuities most likely to be found in round bar stock are:
a) seams.
b) cold shuts.
c) grinding crack.
d) fatigue crack.
a) seams.
Which of the following is a service defect?
a) lack of penetration
b) undercut
c) fatigue crack
d) heat treatment crack
c) fatigue crack
Eddy current method can be used to inspect:
a) conductors.
b) plastics.
c) ceramics.
d) concrete
a) conductors.
Eddy currents travel:
a) in closed paths.
b) in nonconductive materials.
c) axially when testing rod with an encircling coil.
d) perpendicular to the test surface.
a) in closed paths.
At any given instant a spring-loaded internal probe can inspect:
a) one complete circumference of the product.
b) an area roughly defined by the size of the probe coil.
c) one longitudinal line the length of the product.
d) none of the above
b) an area roughly defined by the size of the probe coil.
Some products commonly tested with encircling probes are:
a) rods, tubes and wires.
b) interior of hollow tubes.
c) sheets and metallized foil.
d) all of the above.
a) rods, tubes and wires.
Which of the following eddy current test coil arrangements compares one area of the test specimen,
as a reference standard, to another area on the same specimen simultaneously?
a) Absolute coil
b) Gap coil
c) DC saturation coil
d) Differential coil
d) Differential coil
IACS is a recognized abbreviation for:
a) Induced Alternating Current System.
b) Inductively Activated Comparison System.
c) Internal Applied Current System.
d) International Annealed Copper Standard.
d) International Annealed Copper Standard.
In the IACS system of electrical conductivity measurement, pure copper is arbitrarily assigned the
value of:
a) 0%.
b) 10%.
c) 50%.
d) 100%
d) 100%
Which of the following test frequencies would produce eddy currents with the largest depth of
penetration?
a) 100 Hz
b) 10 kHz
c) 1 MHz
d) 10 MHz
a) 100 Hz
In the following, the metal with the highest electrical conductivity is:
a) copper
b) aluminum
c) silver
d) iron
c) silver
As the temperature of metal increases, the electrical conductivity:
a) increases
b) decreases
c) does not change
d) any of the above may occur depending on the type of metal.
b) decreases
The bores of fastener holes on aircraft are an important source of cracking caused by:
a) fatigue.
b) burst.
c) overloading.
d) both a) and b)
a) fatigue.
A rupture in the material that can be in any direction on the part, and caused by localized stresses
that exceed the tensile strength of the material is:
a) a fatigue crack.
b) a heat treat crack.
c) a seam.
d) a stringer
b) a heat treat crack.
An eddy current probe can consist of:
a) a single test coil.
b) an excitation coil with a separate receiver coil.
c) an excitation coil with a Hall effect sensing detector.
d) all of the above
d) all of the above
Which of the following materials would have the highest resistivity value?
a) Aluminum with a 42% IACS rating
b) Magnesium with a 37% IACS rating
c) Cast steel with a 10.5% IACS rating
d) Zirconium with a 3.4% IACS rating
d) Zirconium with a 3.4% IACS rating
During measurement of conductivity of a specimen the effect of (error from) variations in test part
thickness can be reduced by:
a) increasing test frequency.
b) decreasing test frequency.
c) decreasing fill factor.
d) there is no practical method for reducing this effect.
a) increasing test frequency.
A term used to define the phenomenon where, at very high frequencies, eddy current flow is
restricted to an extremely thin outer layer of the conductor is:
a) skin depth effect.
b) high frequency filtering.
c) low frequency filtering.
d) any of the above.
a) skin depth effect.
To obtain the maximum signal (using a surface probe) from a defect of a given size at a given depth
in a flat conductor there is:
a) an optimum size coil, but no optimum frequency.
b) an optimum frequency, but no optimum size coil.
c) an optimum frequency and optimum size probe.
d) no absolute optimum but use the highest frequency and the smallest coil attainable.
c) an optimum frequency and optimum size probe.
Conductivity instruments can be used to sort materials with different:
a) electrical conductivity.
b) electrical resistivity.
c) magnetic permeability.
d) all of the above
d) all of the above
