Eugene Cawley
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NDE Technician Non Destructive Testing Test sobre ET Level II Practice Test , creado por Eugene Cawley el 18/12/2018.

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Eugene Cawley
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ET Level II Practice Test

Pregunta 1 de 89

1

A method of minimizing the effect of indications caused by
gradual dimensional changes while retaining the indications
caused by discontinuities is too:

Selecciona una de las siguientes respuestas posibles:

  • A. include a high-pass filter in the eddy current test
    equipment.

  • B. include a low-pass filter in the eddy current test
    equipment.

  • C. increase the band pass of the amplifier.

  • D. use the impedance method of testing.

Explicación

Pregunta 2 de 89

1

Which of the following methods may be used to improve the signal-to-noise ratio of an eddy current test system?

Selecciona una de las siguientes respuestas posibles:

  • A. Filtering or differentiation.

  • B. Phase discrimination.

  • C. Integration.

  • D. All of the above.

Explicación

Pregunta 3 de 89

1

In order to decrease the effect on conductivity readings due to variations in test part thickness:

Selecciona una de las siguientes respuestas posibles:

  • A. the test frequency should be increased.

  • B. the test frequency should be decreased.

  • C. the fill factor should be decreased.

  • D. there is no practical method for decreasing this effect.

Explicación

Pregunta 4 de 89

1

When testing by the eddy current method, discontinuities will be most easily detected when the eddy currents are:

Selecciona una de las siguientes respuestas posibles:

  • A. coplanar with the major plane of the discontinuity.

  • B. perpendicular to the major plane of the discontinuity.

  • C. parallel to the major plane of the discontinuity.

  • D. 90 degrees out of phase with the current in the coil.

Explicación

Pregunta 5 de 89

1

A term used to describe the effect observed due to a change in the electromagnetic coupling between a test specimen and a probe coil when the distance of separation between them is varied is:

Selecciona una de las siguientes respuestas posibles:

  • A. fill factor.

  • B. edge effect.

  • C. end effect.

  • D. lift-off.

Explicación

Pregunta 6 de 89

1

A term used to define the phenomenon where, at very high frequencies, the eddy current flow is restricted to an extremely thin outer layer of the conductor is:

Selecciona una de las siguientes respuestas posibles:

  • A. skin effect.

  • B. high-frequency filtration.

  • C. low-frequency filtration.

  • D. any one of the above.

Explicación

Pregunta 7 de 89

1

The fill factor when a 1/2-inch diameter bar is inserted in a 1-inch diameter coil is:

Selecciona una de las siguientes respuestas posibles:

  • A. 0.5 or (50%)

  • B. 0.75 or (75%)

  • C. 1.0 or (100%)

  • D. 0.25 or (25%)

Explicación

Pregunta 8 de 89

1

The term used to define the difference between actual instrument output and expected output as defined by a straight line calibration curve is:

Selecciona una de las siguientes respuestas posibles:

  • A. phase shift.

  • B. nonlinearity.

  • C. lift-off.

  • D. skin effect.

Explicación

Pregunta 9 de 89

1

Which of the following could be used to suppress unwanted high-frequency harmonics?

Selecciona una de las siguientes respuestas posibles:

  • A. Low-pass filter.

  • B. Oscillator.

  • C. Phase discriminator.

  • D. High-pass filter.

Explicación

Pregunta 10 de 89

1

The impedance change of an eddy current test coil due to a change in test part characteristics can be most easily analyzed as a combined change in:

Selecciona una de las siguientes respuestas posibles:

  • A. capacitive reactance and resistance.

  • B. harmonic frequencies and inductive reactance.

  • C. signal amplitude and phase.

  • D. retentivity and harmonic frequencies.

Explicación

Pregunta 11 de 89

1

The inductive reactance of a test coil can be calculated using the formula:

Selecciona una de las siguientes respuestas posibles:

  • A. XL = 2 π L

  • B. XL = 1/2 π L

  • C. XL = 2 π f L

  • D. XL = W 2 π f

Explicación

Pregunta 12 de 89

1

When conducting an eddy current test, variations in the test material can be detected as variations in:

Selecciona una de las siguientes respuestas posibles:

  • A. test speed.

  • B. impedance of a pickup coil.

  • C. none of the above.

  • D. all of the above.

Explicación

Pregunta 13 de 89

1

A term used to define two or more coils electrically connected in opposition such that any electromagnetic condition which is not common to both a test specimen and a reference specimen will produce an unbalance in the system is:

Selecciona una de las siguientes respuestas posibles:

  • A. differential.

  • B. absolute.

  • C. laminar.

  • D. flying probes.

Explicación

Pregunta 14 de 89

1

Tubing is generally inspected using:

Selecciona una de las siguientes respuestas posibles:

  • A. U-shaped coils.

  • B. internal coils.

  • C. encircling coils.

  • D. Either B or C depending on configuration.

Explicación

Pregunta 15 de 89

1

When testing small parts in an eddy current encircling coil for permeability measurements, which of the following test parameters may be considered important?

Selecciona una de las siguientes respuestas posibles:

  • A. Length of the test sample.

  • B. Thickness of the test sample.

  • C. Cross-sectional area of the test sample.

  • D. all of the above.

Explicación

Pregunta 16 de 89

1

In a test coil consisting of both a primary and secondary winding, the voltage across the secondary is a function of:

Selecciona una de las siguientes respuestas posibles:

  • A. test material permeability.

  • B. test frequency.

  • C. geometry of the test object.

  • D. all of the above.

Explicación

Pregunta 17 de 89

1

Eddy current testing relies on the principle of:

Selecciona una de las siguientes respuestas posibles:

  • A. magnetostriction.

  • B. electromagnetic induction.

  • C. piezoelectric energy conversion.

  • D. magnetomotive force.

Explicación

Pregunta 18 de 89

1

When the H field strength around a material is increased and
then decreased to zero, the induction field B within the part
does not return to zero. The term to define this B value when H has returned to zero is:

Selecciona una de las siguientes respuestas posibles:

  • A. coercive force.

  • B. residual magnetism.

  • C. saturation value.

  • D. hysteresis loss.

Explicación

Pregunta 19 de 89

1

The term used to define the value of H field required to
decrease the remanence of a material to zero is:

Selecciona una de las siguientes respuestas posibles:

  • A. coercive force.

  • B. magnetizing force.

  • C. back emf.

  • D. the overlap value.

Explicación

Pregunta 20 de 89

1

The three major specimen parameters which influence eddy current testing are:

Selecciona una de las siguientes respuestas posibles:

  • A. electrical conductivity, frequency, and material geometry.

  • B. density, permeability, and frequency.

  • C. electrical conductivity, permeability, and material geometry.

  • D. thermal conductivity, electrical conductivity, and permeability.

Explicación

Pregunta 21 de 89

1

Doubling the number of turns on a coil will:

Selecciona una de las siguientes respuestas posibles:

  • A. double the indicators.

  • B. halve the inductance.

  • C. decrease the inductance by a factor of four.

  • D. increase the inductance by a factor of four.

Explicación

Pregunta 22 de 89

1

Frequency ratio, f/fg can be defined as:

Selecciona una de las siguientes respuestas posibles:

  • A. the argument of the mathematical function describing the electromagnetic field within the test specimen.

  • B. test frequency divided by limit frequency.

  • C. neither of these.

  • D. both of these.

Explicación

Pregunta 23 de 89

1

When testing tubing, using and encircling (OD) coil, what is the
phase relationship of the output signals from identical ID and OD
discontinuities?

Selecciona una de las siguientes respuestas posibles:

  • A. The signals are in phase.

  • B. The phase of the OD discontinuity leads the phase of the ID
    discontinuity.

  • C. The phase of the OD discontinuity lags the phase of the ID
    discontinuity.

  • D. Indeterminate.

Explicación

Pregunta 24 de 89

1

A term used to define an instrumentation technique which discriminates between variables in the test part by the different phase angle changes which these conditions produced in the test signal is:

Selecciona una de las siguientes respuestas posibles:

  • A. phase distortion.

  • B. phase shifting.

  • C. phase discrimination.

  • D. phase analysis.

Explicación

Pregunta 25 de 89

1

If the characteristic frequency (fg) of a material is 125 Hz, the test frequency required to give an f/fg ratio of 10 would be:

Selecciona una de las siguientes respuestas posibles:

  • A. 1.25 Hz.

  • B. 12.5 Hz.

  • C. 1.25 kHz.

  • D. 12.5 kHz.

Explicación

Pregunta 26 de 89

1

A term used to define any change in a sinusoidal signal when the output is not a linear reproduction of the input is:

Selecciona una de las siguientes respuestas posibles:

  • A. distortion.

  • B. linearity.

  • C. phase shifting.

  • D. dynamic range

Explicación

Pregunta 27 de 89

1

At a fixed test frequency, in which of the following materials will the eddy current penetration be greatest?

Selecciona una de las siguientes respuestas posibles:

  • A. Aluminum (35 percent IACS conductivity)

  • B. Brass (15 percent IACS conductivity)

  • C. Copper (95 percent IACS conductivity)

  • D. Lead (7 percent IACS conductivity)

Explicación

Pregunta 28 de 89

1

The heating effect in magnetic materials caused by the work
required to rotate magnetic domains can be eliminated by:

Selecciona una de las siguientes respuestas posibles:

  • A. increasing the rate of displacement of the specimen through the coil.

  • B. magnetically saturating the test specimen.

  • C. decreasing the rate of displacement of the test specimen through the test coil.

  • D. testing in an air-conditioned room.

Explicación

Pregunta 29 de 89

1

If the test frequency increases while the field strength is held constant, the surface eddy current density:

Selecciona una de las siguientes respuestas posibles:

  • A. decreases.

  • B. increases.

  • C. remains the same.

  • D. could do any of the above.

Explicación

Pregunta 30 de 89

1

As the fill factor decreases, the impedance variation of a
pickup coil produced by a given change in conductivity will:

Selecciona una de las siguientes respuestas posibles:

  • A. increase.

  • B. remain the same.

  • C. decrease.

  • D. could do any of the above.

Explicación

Pregunta 31 de 89

1

Which of the following would be easier to detect in tubing by the eddy current method using the self-comparison differential coil arrangement?

Selecciona una de las siguientes respuestas posibles:

  • A. Gradual changes in diameter.

  • B. Gradual changes in conductivity.

  • C. Changes in temperature.

  • D. Short flaws.

Explicación

Pregunta 32 de 89

1

The magnetic domains in an unmagnetized ferromagnetic material are:

Selecciona una de las siguientes respuestas posibles:

  • A. arranged to facilitate the conduction of electrons.

  • B. randomly oriented and neutralize each other.

  • C. uniformly oriented.

  • D. create a major north and south pole in the material.

Explicación

Pregunta 33 de 89

1

When a magnetic material is placed in a region of an applied magnetizing force (H), magnetic field (B) is developed in the material by means of:

Selecciona una de las siguientes respuestas posibles:

  • A. induction.

  • B. conduction.

  • C. heat transfer.

  • D. magnetic domain transfer.

Explicación

Pregunta 34 de 89

1

To eliminate any dependence upon the number of turns of a test coil, the inductance values of an impedance diagram are:

Selecciona una de las siguientes respuestas posibles:

  • A. disregarded.

  • B. normalized.

  • C. corrected to a value of 1.

  • D. none of the above.

Explicación

Pregunta 35 de 89

1

A term used to define a system which indicates only the magnitude of variations in the total coil impedance regardless of the phase or direction in which it occurs on an impedance plane is:

Selecciona una de las siguientes respuestas posibles:

  • A. inductive reactance magnitude system.

  • B. feedback-controlled system.

  • C. impedance-magnitude system.

  • D. impedance vector analysis system.

Explicación

Pregunta 36 de 89

1

When eddy current testing tubing with a system that includes a frequency discriminating circuit, which of the following variables would we classified as a high-frequency variable?

Selecciona una de las siguientes respuestas posibles:

  • A. Small discontinuities.

  • B. Conductivity changes.

  • C. Diameter changes

  • D. Wall thickness variations.

Explicación

Pregunta 37 de 89

1

A major problem associated with the eddy current test method is the:

Selecciona una de las siguientes respuestas posibles:

  • A. inability of eddy current testing to accurately measure conductivity.

  • B. need to test at low speeds to prevent skipping.

  • C. large number of known or unknown variables which appear in the output indication.

  • D. inability of eddy current testing to detect small discontinuities.

Explicación

Pregunta 38 de 89

1

The atoms of a metal showing magnetic characteristics are grouped into regions which are the smallest known permanent magnets. These regions are called:

Selecciona una de las siguientes respuestas posibles:

  • A. lattice structures.

  • B. cells.

  • C. domains.

  • D. planetary spins.

Explicación

Pregunta 39 de 89

1

When a coil's magnetizing force is applied to a ferromagnetic
material, the flux density in the material is:

Selecciona una de las siguientes respuestas posibles:

  • A. less than the flux density generated by the test coil
    because of heat losses.

  • B. less than the flux density generated by the test coil
    because of resistivity.

  • C. the same as the flux density generated by the test coil.

  • D. greater than the flux density generated by the test coil.

Explicación

Pregunta 40 de 89

1

The flux density in a magnetic material is usually designed by the:

Selecciona una de las siguientes respuestas posibles:

  • A. Greek symbol “μ” (mu)

  • B. Greek symbol “∆” (delta)

  • C. letter B

  • D. letter H

Explicación

Pregunta 41 de 89

1

The magnetizing force of an eddy current test coil is usually designated by the:

Selecciona una de las siguientes respuestas posibles:

  • A. Greek symbol “μ” (mu)

  • B. Greek symbol “∆” (delta)

  • C. letter B

  • D. letter H

Explicación

Pregunta 42 de 89

1

The thickness of nonconductive coatings on a conductive base can be most simply measured by:

Selecciona una de las siguientes respuestas posibles:

  • A. observing the lift-off effect caused by the coating.

  • B. testing both sides of the specimen.

  • C. varying the current in the test coil.

  • D. varying the test frequency over a given range during the test.

Explicación

Pregunta 43 de 89

1

The use of magnetic shielding around the exciting coil will
generally:

Selecciona una de las siguientes respuestas posibles:

  • A. increase the magnetic field extension but decreases the eddy
    current penetration.

  • B. increase the magnetic field extension and eddy current
    penetration.

  • C. decrease the magnetic field extension but increase the eddy
    current penetration.

  • D. decrease the magnetic field extension and eddy current
    penetration.

Explicación

Pregunta 44 de 89

1

Which of the following is not a factor that affects the
inductance of an eddy current test coil?

Selecciona una de las siguientes respuestas posibles:

  • A. Diameter of coils.

  • B. Test frequency.

  • C. Overall shape of the coils.

  • D. Distance from other coils.

Explicación

Pregunta 45 de 89

1

An out-of-phase condition between current and voltage:

Selecciona una de las siguientes respuestas posibles:

  • A. can exist only in the primary winding of an eddy current
    coil.

  • B. can exist only in the secondary winding of an eddy current
    coil.

  • C. can exist in both the primary and secondary windings of an
    eddy current coil.

  • D. exists only in the test specimen.

Explicación

Pregunta 46 de 89

1

A term used to define a surface coil mounted so that the coil can be rotated about the circumference of a test specimen is:

Selecciona una de las siguientes respuestas posibles:

  • A. bobbin coil.

  • B. encircling coil.

  • C. spinning coil.

  • D. gap coil.

Explicación

Pregunta 47 de 89

1

A term used to define an eddy current test coil which uses magnetic material to purposely shape the magnetic field is:

Selecciona una de las siguientes respuestas posibles:

  • A. bobbin coil.

  • B. encircling coil.

  • C. spinning coil.

  • D. gap coil.

Explicación

Pregunta 48 de 89

1

The vector-point, ellipse, and linear time-base methods are all subdivisions of the:

Selecciona una de las siguientes respuestas posibles:

  • A. impedance method of testing.

  • B. the modulation analysis method of testing.

  • C. the phase analysis method of testing.

  • D. none of the above.

Explicación

Pregunta 49 de 89

1

It is frequently possible to separate the conductivity variable from the permeability and dimensional variables when using:

Selecciona una de las siguientes respuestas posibles:

  • A. the vector-point method of testing.

  • B. the ellipse method of testing.

  • C. the linear time-base method of testing.

  • D. any of the above methods of testing.

Explicación

Pregunta 50 de 89

1

When eddy current testing by the ellipse method, the normal indication when the test specimen and reference standard are the same is approximately:

Selecciona una de las siguientes respuestas posibles:

  • A. a straight horizontal line on a cathode ray tube.

  • B. an ellipse on a cathode ray tube.

  • C. a null reading on a meter.

  • D. a clean base line on a strip chart.

Explicación

Pregunta 51 de 89

1

When eddy current testing by the ellipse method, one variable may be indicated by the angle of the ellipse or straight line while another variable may be indicated by the:

Selecciona una de las siguientes respuestas posibles:

  • A. brightness of the ellipse.

  • B. horizontal length of the straight line.

  • C. size of the ellipse opening.

  • D. sinusoidal shape of the waveform.

Explicación

Pregunta 52 de 89

1

When eddy current testing by the linear time-base method, what is applied to the vertical deflection plates of a cathode ray tube when the test specimen and reference standard are the same and the balance controls are properly adjusted?

Selecciona una de las siguientes respuestas posibles:

  • A. A sinusoidal wave in phase with the timing voltage.

  • B. A sinusoidal wave 90 degrees out of phase with the timing
    voltage.

  • C. A sawtooth waveform.

  • D. Zero net voltage.

Explicación

Pregunta 53 de 89

1

When eddy current testing by the linear time-base method, what is applied to the vertical deflection plates of a cathode ray tube when a condition of unbalance exists between the test specimen and the reference standard?

Selecciona una de las siguientes respuestas posibles:

  • A. A sinusoidal wave

  • B. A sawtooth wave

  • C. A square wave

  • D. No voltage

Explicación

Pregunta 54 de 89

1

The conductivity value for a metal is a function of the:

Selecciona una de las siguientes respuestas posibles:

  • A. heat treatment given the metal.

  • B. cold working performed on the metal.

  • C. aging process used on the metal.

  • D. all of the above.

Explicación

Pregunta 55 de 89

1

The ratio of the specific diameter of a probe to the minimum discontinuity of interest should be:

Selecciona una de las siguientes respuestas posibles:

  • A. less then 2.

  • B. greater than 2.

  • C. greater than 4.

  • D. greater than 10.

Explicación

Pregunta 56 de 89

1

Which of the following materials would be more likely used as a mounting material for a probe coil?

Selecciona una de las siguientes respuestas posibles:

  • A. Aluminum

  • B. Fiberglass

  • C. Copper

  • D. Steel

Explicación

Pregunta 57 de 89

1

A term used to define a surface or internal rupture which is attributed to processing at too low a temperature or excessive working or metal movement during the forging, rolling, or extruding operation is:

Selecciona una de las siguientes respuestas posibles:

  • A. cold shut.

  • B. microshrinkage.

  • C. burst.

  • D. inclusion.

Explicación

Pregunta 58 de 89

1

A term used to define the timing relationships involved in alternating current signals is:

Selecciona una de las siguientes respuestas posibles:

  • A. magnitude.

  • B. phase.

  • C. impedance.

  • D. reactance.

Explicación

Pregunta 59 de 89

1

When eddy current testing a nonferrous material, the choice of test frequency is determined by the:

Selecciona una de las siguientes respuestas posibles:

  • A. degree of phase discrimination required.

  • B. eddy current penetration needed.

  • C. rate of response required.

  • D. all of the above.

Explicación

Pregunta 60 de 89

1

When testing ferrous materials, a small but detectable portion of the magnetic flux in the material will pass outside the metal when a surface discontinuity is encountered. This flux is called:

Selecciona una de las siguientes respuestas posibles:

  • A. air flux.

  • B. leakage flux.

  • C. induced flux.

  • D. none of the above.

Explicación

Pregunta 61 de 89

1

A term to define a property of a test system which enables the separation of signals due to discontinuities in the test specimen that are located in close proximity to each other is:

Selecciona una de las siguientes respuestas posibles:

  • A. dynamic range.

  • B. sensitivity.

  • C. linearity.

  • D. discontinuity resolution.

Explicación

Pregunta 62 de 89

1

A term used to define a material having a permeability less than that of a vacuum is:

Selecciona una de las siguientes respuestas posibles:

  • A. diamagnetic.

  • B. ferromagnetic.

  • C. paramagnetic.

  • D. magnetic.

Explicación

Pregunta 63 de 89

1

The inductive reactance of a coil is measured in units of:

Selecciona una de las siguientes respuestas posibles:

  • A. mhos.

  • B. ohms.

  • C. henrys.

  • D. gauss.

Explicación

Pregunta 64 de 89

1

Which of the following coil arrangements would eliminate or decrease the effects of minor variations in diameter, chemical composition, hardness, etc., which occur gradually along the length of a wire?

Selecciona una de las siguientes respuestas posibles:

  • A. External reference differential

  • B. Self-comparison differential

  • C. Single coil absolute

  • D. Double coil absolute

Explicación

Pregunta 65 de 89

1

Which of the following conditions are not important when
selecting specimens to be used as reference standards?

Selecciona una de las siguientes respuestas posibles:

  • A. The specimen should be of the same size and shape as the piece to be tested.

  • B. The specimen should have the same heat treatment as the piece to be tested.

  • C. The surface finish of the specimen should be the same as the piece to be tested.

  • D. If the material is aluminum, the surface should be anodized.

Explicación

Pregunta 66 de 89

1

An eddy current test coil's magnetic field intensity in air:

Selecciona una de las siguientes respuestas posibles:

  • A. increases with distance outside the coil and varies across the diameter inside the coil.

  • B. decreases with distance outside the coil and varies across the diameter inside the coil.

  • C. decreases with distance outside the coil and is assumed to be constant across the diameter inside the coil.

  • D. increases with distance outside the coil and is assumed to be constant across the diameter inside the coil.

Explicación

Pregunta 67 de 89

1

The circuits which make it possible to minimize the effect of signals caused by variables of no interest on the readout mechanism are based on differences in:

Selecciona una de las siguientes respuestas posibles:

  • A. amplitude.

  • B. phase

  • C. frequency.

  • D. any one of a combination of the quantities listed above.

Explicación

Pregunta 68 de 89

1

When a nonmagnetic rod is placed inside an eddy current test
coil:

Selecciona una de las siguientes respuestas posibles:

  • A. the magnetic field generated by the coil is increased in
    intensity.

  • B. the distribution of eddy currents is uniform through the
    rod's cross section.

  • C. the distribution of eddy currents is at a maximum at the rod's
    surface, or near the surface, and decreases to essentially zero
    at the rod's center.

  • D. the temperature of the rod decreases.

Explicación

Pregunta 69 de 89

1

The symbol commonly used to signify impedance is:

Selecciona una de las siguientes respuestas posibles:

  • A. Z

  • B. X

  • C. R

  • D. Xc

Explicación

Pregunta 70 de 89

1

A decrease in conductivity is equivalent to:

Selecciona una de las siguientes respuestas posibles:

  • A. an increase in permeability.

  • B. an increase in resistivity.

  • C. a decrease in permeability.

  • D. a decrease in resistivity.

Explicación

Pregunta 71 de 89

1

If the conductivity of a test part in an eddy current test coil decreases, the magnitude of the eddy currents at a given depth in the test specimen:

Selecciona una de las siguientes respuestas posibles:

  • A. increases.

  • B. remains the same.

  • C. decreases.

  • D. may increase or decrease.

Explicación

Pregunta 72 de 89

1

When the voltage applied to a circuit and the current through the circuit both reach their maximums and minimums at the same time, the voltage and current are:

Selecciona una de las siguientes respuestas posibles:

  • A. additive.

  • B. in phase.

  • C. regenerative.

  • D. out of phase.

Explicación

Pregunta 73 de 89

1

Which of the following is not a commonly used eddy current testing readout mechanism?

Selecciona una de las siguientes respuestas posibles:

  • A. Signal generator.

  • B. Meter.

  • C. Cathode ray tube.

  • D. Strip-chart recorder.

Explicación

Pregunta 74 de 89

1

Which of the following materials would have the highest resistivity value?

Selecciona una de las siguientes respuestas posibles:

  • A. Aluminum with a 42 percent IACS rating.

  • B. Magnesium with a 37 percent IACS rating.

  • C. Cast steel with a 10.7 percent IACS rating.

  • D. Zirconium with a 3.4 percent IACS rating

Explicación

Pregunta 75 de 89

1

The ratio of a material's flux density to a test coil's magnetizing force, (B/H), can be used to determine the
material's:

Selecciona una de las siguientes respuestas posibles:

  • A. conductivity.

  • B. resistivity.

  • C. lift-off.

  • D. permeability.

Explicación

Pregunta 76 de 89

1

The magnetic field generated by eddy currents induced in a test specimen:

Selecciona una de las siguientes respuestas posibles:

  • A. opposes the magnetic field that induced the eddy currents.

  • B. reinforces the magnetic field that induced the eddy
    currents.

  • C. cancels the magnetic field that induced the eddy currents.

  • D. has no effect on the magnetic field that induced the eddy
    currents.

Explicación

Pregunta 77 de 89

1

The impedance of a test coil usually can be represented by the vector sum of:

Selecciona una de las siguientes respuestas posibles:

  • A. inductive reactance and resistance.

  • B. capacitive reactance and resistance.

  • C. inductive reactance and capacitive reactance.

  • D. inductance and capacitance

Explicación

Pregunta 78 de 89

1

For age hardenable aluminum and titanium alloys, changes in hardness are indicated by changes in:

Selecciona una de las siguientes respuestas posibles:

  • A. retentivity.

  • B. permeability.

  • C. conductivity.

  • D. magnetostriction.

Explicación

Pregunta 79 de 89

1

The penetration of eddy currents in a conductive material is
decreased when:

Selecciona una de las siguientes respuestas posibles:

  • A. test frequency or conductivity of the specimen is decreased.

  • B. test frequency is decreased or conductivity of the specimen is increased.

  • C. test frequency, conductivity of the specimen or permeability of the specimen are increased.

  • D. permeability of the specimen is decreased.

Explicación

Pregunta 80 de 89

1

When the electrical current in an eddy current coil reverses
direction:

Selecciona una de las siguientes respuestas posibles:

  • A. the direction of the eddy currents in a part remains the
    same.

  • B. the eddy currents in the test part will change phase by 45
    degrees.

  • C. the direction of the eddy currents in the part also
    reverses.

  • D. the eddy currents in the part remain the same.

Explicación

Pregunta 81 de 89

1

When testing magnetic materials in an ac field, increasing the field strength:

Selecciona una de las siguientes respuestas posibles:

  • A. has no effect.

  • B. increases eddy current penetration.

  • C. decreases eddy current penetration.

  • D. decreases eddy current penetration to some minimum value, and then increases it to its maximum value when the specimen becomes magnetically saturated.

Explicación

Pregunta 82 de 89

1

Impedance diagrams have been mathematically derived and experimentally verified for materials of any conductivity and permeability having rectangular, cylindrical, or spherical symmetry. To test all specimens of similar geometry under the same condition, it is only necessary to choose a test frequency, f, so that frequency ratio f/fg lies at the same point on the impedance diagram for each specimen. This principle is based upon:

Selecciona una de las siguientes respuestas posibles:

  • A. Ohm's Law.

  • B. Kirchoff's Law.

  • C. the Similarity Law.

  • D. none of the above.

Explicación

Pregunta 83 de 89

1

To be useful, limit frequency equation must be:

Selecciona una de las siguientes respuestas posibles:

  • A. used with their impedance diagrams.

  • B. used to determine their impedance diagrams.

  • C. both of these.

  • D. neither of these.

Explicación

Pregunta 84 de 89

1

When a rod is placed in an encircling type of coil, the density of eddy currents will be the greatest:

Selecciona una de las siguientes respuestas posibles:

  • A. at the surface.

  • B. at the center.

  • C. midway between the surface and the center.

  • D. none of the above.

Explicación

Pregunta 85 de 89

1

The term fill factor applies to:

Selecciona una de las siguientes respuestas posibles:

  • A. a surface coil.

  • B. coaxial cable.

  • C. an encircling coil.

  • D. all of the above.

Explicación

Pregunta 86 de 89

1

An eddy current system using handling equipment with automatic marking of the defective areas primarily makes it possible to:

Selecciona una de las siguientes respuestas posibles:

  • A. remove defective areas of the product, if desired.

  • B. eliminate test surface contamination.

  • C. allow an inexperienced operator to establish the defect cause.

  • D. pass rejectable material.

Explicación

Pregunta 87 de 89

1

Two test coils are often used in a bridge circuit to:

Selecciona una de las siguientes respuestas posibles:

  • A. eliminate skin effect.

  • B. determine the differences between a known standard sample.

  • C. increase the conductivity of the circuit.

  • D. decrease the system sensitivity.

Explicación

Pregunta 88 de 89

1

When inspecting ferromagnetic materials, relatively low
frequencies are normally used because of the:

Selecciona una de las siguientes respuestas posibles:

  • A. low penetrability of these materials.

  • B. higher resolution.

  • C. lower resolution.

  • D. higher penetrability of these materials.

Explicación

Pregunta 89 de 89

1

In modulation analysis testing, which of the following would not modulate the test frequency applied to the test coil?

Selecciona una de las siguientes respuestas posibles:

  • A. Discontinuities in the test specimen.

  • B. Dimension changes of the test specimen.

  • C. Chemical composition of the test specimen.

  • D. A filter in the test circuit.

Explicación