Eugene Cawley
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NDE Technician Non Destructive Testing Quiz sobre ET Level II Practice Test , criado por Eugene Cawley em 18-12-2018.

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Eugene Cawley
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ET Level II Practice Test

Questão 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:

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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?

Selecione uma das seguintes:

  • A. Filtering or differentiation.

  • B. Phase discrimination.

  • C. Integration.

  • D. All of the above.

Explicação

Questão 3 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 4 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. fill factor.

  • B. edge effect.

  • C. end effect.

  • D. lift-off.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. skin effect.

  • B. high-frequency filtration.

  • C. low-frequency filtration.

  • D. any one of the above.

Explicação

Questão 7 de 89

1

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

Selecione uma das seguintes:

  • A. 0.5 or (50%)

  • B. 0.75 or (75%)

  • C. 1.0 or (100%)

  • D. 0.25 or (25%)

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. phase shift.

  • B. nonlinearity.

  • C. lift-off.

  • D. skin effect.

Explicação

Questão 9 de 89

1

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

Selecione uma das seguintes:

  • A. Low-pass filter.

  • B. Oscillator.

  • C. Phase discriminator.

  • D. High-pass filter.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. capacitive reactance and resistance.

  • B. harmonic frequencies and inductive reactance.

  • C. signal amplitude and phase.

  • D. retentivity and harmonic frequencies.

Explicação

Questão 11 de 89

1

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

Selecione uma das seguintes:

  • A. XL = 2 π L

  • B. XL = 1/2 π L

  • C. XL = 2 π f L

  • D. XL = W 2 π f

Explicação

Questão 12 de 89

1

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

Selecione uma das seguintes:

  • A. test speed.

  • B. impedance of a pickup coil.

  • C. none of the above.

  • D. all of the above.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. differential.

  • B. absolute.

  • C. laminar.

  • D. flying probes.

Explicação

Questão 14 de 89

1

Tubing is generally inspected using:

Selecione uma das seguintes:

  • A. U-shaped coils.

  • B. internal coils.

  • C. encircling coils.

  • D. Either B or C depending on configuration.

Explicação

Questão 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?

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. test material permeability.

  • B. test frequency.

  • C. geometry of the test object.

  • D. all of the above.

Explicação

Questão 17 de 89

1

Eddy current testing relies on the principle of:

Selecione uma das seguintes:

  • A. magnetostriction.

  • B. electromagnetic induction.

  • C. piezoelectric energy conversion.

  • D. magnetomotive force.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. coercive force.

  • B. residual magnetism.

  • C. saturation value.

  • D. hysteresis loss.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. coercive force.

  • B. magnetizing force.

  • C. back emf.

  • D. the overlap value.

Explicação

Questão 20 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 21 de 89

1

Doubling the number of turns on a coil will:

Selecione uma das seguintes:

  • 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.

Explicação

Questão 22 de 89

1

Frequency ratio, f/fg can be defined as:

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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?

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. phase distortion.

  • B. phase shifting.

  • C. phase discrimination.

  • D. phase analysis.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. 1.25 Hz.

  • B. 12.5 Hz.

  • C. 1.25 kHz.

  • D. 12.5 kHz.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. distortion.

  • B. linearity.

  • C. phase shifting.

  • D. dynamic range

Explicação

Questão 27 de 89

1

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

Selecione uma das seguintes:

  • A. Aluminum (35 percent IACS conductivity)

  • B. Brass (15 percent IACS conductivity)

  • C. Copper (95 percent IACS conductivity)

  • D. Lead (7 percent IACS conductivity)

Explicação

Questão 28 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 29 de 89

1

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

Selecione uma das seguintes:

  • A. decreases.

  • B. increases.

  • C. remains the same.

  • D. could do any of the above.

Explicação

Questão 30 de 89

1

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

Selecione uma das seguintes:

  • A. increase.

  • B. remain the same.

  • C. decrease.

  • D. could do any of the above.

Explicação

Questão 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?

Selecione uma das seguintes:

  • A. Gradual changes in diameter.

  • B. Gradual changes in conductivity.

  • C. Changes in temperature.

  • D. Short flaws.

Explicação

Questão 32 de 89

1

The magnetic domains in an unmagnetized ferromagnetic material are:

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. induction.

  • B. conduction.

  • C. heat transfer.

  • D. magnetic domain transfer.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. disregarded.

  • B. normalized.

  • C. corrected to a value of 1.

  • D. none of the above.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. inductive reactance magnitude system.

  • B. feedback-controlled system.

  • C. impedance-magnitude system.

  • D. impedance vector analysis system.

Explicação

Questão 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?

Selecione uma das seguintes:

  • A. Small discontinuities.

  • B. Conductivity changes.

  • C. Diameter changes

  • D. Wall thickness variations.

Explicação

Questão 37 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. lattice structures.

  • B. cells.

  • C. domains.

  • D. planetary spins.

Explicação

Questão 39 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 40 de 89

1

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

Selecione uma das seguintes:

  • A. Greek symbol “μ” (mu)

  • B. Greek symbol “∆” (delta)

  • C. letter B

  • D. letter H

Explicação

Questão 41 de 89

1

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

Selecione uma das seguintes:

  • A. Greek symbol “μ” (mu)

  • B. Greek symbol “∆” (delta)

  • C. letter B

  • D. letter H

Explicação

Questão 42 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 43 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 44 de 89

1

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

Selecione uma das seguintes:

  • A. Diameter of coils.

  • B. Test frequency.

  • C. Overall shape of the coils.

  • D. Distance from other coils.

Explicação

Questão 45 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. bobbin coil.

  • B. encircling coil.

  • C. spinning coil.

  • D. gap coil.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. bobbin coil.

  • B. encircling coil.

  • C. spinning coil.

  • D. gap coil.

Explicação

Questão 48 de 89

1

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

Selecione uma das seguintes:

  • A. impedance method of testing.

  • B. the modulation analysis method of testing.

  • C. the phase analysis method of testing.

  • D. none of the above.

Explicação

Questão 49 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. brightness of the ellipse.

  • B. horizontal length of the straight line.

  • C. size of the ellipse opening.

  • D. sinusoidal shape of the waveform.

Explicação

Questão 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?

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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?

Selecione uma das seguintes:

  • A. A sinusoidal wave

  • B. A sawtooth wave

  • C. A square wave

  • D. No voltage

Explicação

Questão 54 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 55 de 89

1

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

Selecione uma das seguintes:

  • A. less then 2.

  • B. greater than 2.

  • C. greater than 4.

  • D. greater than 10.

Explicação

Questão 56 de 89

1

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

Selecione uma das seguintes:

  • A. Aluminum

  • B. Fiberglass

  • C. Copper

  • D. Steel

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. cold shut.

  • B. microshrinkage.

  • C. burst.

  • D. inclusion.

Explicação

Questão 58 de 89

1

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

Selecione uma das seguintes:

  • A. magnitude.

  • B. phase.

  • C. impedance.

  • D. reactance.

Explicação

Questão 59 de 89

1

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

Selecione uma das seguintes:

  • A. degree of phase discrimination required.

  • B. eddy current penetration needed.

  • C. rate of response required.

  • D. all of the above.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. air flux.

  • B. leakage flux.

  • C. induced flux.

  • D. none of the above.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. dynamic range.

  • B. sensitivity.

  • C. linearity.

  • D. discontinuity resolution.

Explicação

Questão 62 de 89

1

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

Selecione uma das seguintes:

  • A. diamagnetic.

  • B. ferromagnetic.

  • C. paramagnetic.

  • D. magnetic.

Explicação

Questão 63 de 89

1

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

Selecione uma das seguintes:

  • A. mhos.

  • B. ohms.

  • C. henrys.

  • D. gauss.

Explicação

Questão 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?

Selecione uma das seguintes:

  • A. External reference differential

  • B. Self-comparison differential

  • C. Single coil absolute

  • D. Double coil absolute

Explicação

Questão 65 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 66 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. amplitude.

  • B. phase

  • C. frequency.

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

Explicação

Questão 68 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 69 de 89

1

The symbol commonly used to signify impedance is:

Selecione uma das seguintes:

  • A. Z

  • B. X

  • C. R

  • D. Xc

Explicação

Questão 70 de 89

1

A decrease in conductivity is equivalent to:

Selecione uma das seguintes:

  • A. an increase in permeability.

  • B. an increase in resistivity.

  • C. a decrease in permeability.

  • D. a decrease in resistivity.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. increases.

  • B. remains the same.

  • C. decreases.

  • D. may increase or decrease.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. additive.

  • B. in phase.

  • C. regenerative.

  • D. out of phase.

Explicação

Questão 73 de 89

1

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

Selecione uma das seguintes:

  • A. Signal generator.

  • B. Meter.

  • C. Cathode ray tube.

  • D. Strip-chart recorder.

Explicação

Questão 74 de 89

1

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

Selecione uma das seguintes:

  • 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

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. conductivity.

  • B. resistivity.

  • C. lift-off.

  • D. permeability.

Explicação

Questão 76 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 77 de 89

1

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

Selecione uma das seguintes:

  • A. inductive reactance and resistance.

  • B. capacitive reactance and resistance.

  • C. inductive reactance and capacitive reactance.

  • D. inductance and capacitance

Explicação

Questão 78 de 89

1

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

Selecione uma das seguintes:

  • A. retentivity.

  • B. permeability.

  • C. conductivity.

  • D. magnetostriction.

Explicação

Questão 79 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 80 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 81 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 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:

Selecione uma das seguintes:

  • A. Ohm's Law.

  • B. Kirchoff's Law.

  • C. the Similarity Law.

  • D. none of the above.

Explicação

Questão 83 de 89

1

To be useful, limit frequency equation must be:

Selecione uma das seguintes:

  • A. used with their impedance diagrams.

  • B. used to determine their impedance diagrams.

  • C. both of these.

  • D. neither of these.

Explicação

Questão 84 de 89

1

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

Selecione uma das seguintes:

  • A. at the surface.

  • B. at the center.

  • C. midway between the surface and the center.

  • D. none of the above.

Explicação

Questão 85 de 89

1

The term fill factor applies to:

Selecione uma das seguintes:

  • A. a surface coil.

  • B. coaxial cable.

  • C. an encircling coil.

  • D. all of the above.

Explicação

Questão 86 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 87 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 88 de 89

1

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

Selecione uma das seguintes:

  • A. low penetrability of these materials.

  • B. higher resolution.

  • C. lower resolution.

  • D. higher penetrability of these materials.

Explicação

Questão 89 de 89

1

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

Selecione uma das seguintes:

  • 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.

Explicação