Free ASNT Eddy Current Questions and Answers

Question 1

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

Accepted Answer

Include a high pass filter in the eddy current test equipment

Answer

Include a low pass filter in the eddy current test equipment

Answer

Increase the bandpass of the amplifier

Answer

Use the impedance method of testing

Question 2

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

Accepted Answer

All of the above

Answer

Filtering or differentiation

Answer

Phase discrimination

Answer

Integration

Question 3

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

Accepted Answer

The test frequency should be increased

Answer

The test frequency should be decreased

Answer

The fill factor should be decreased

Answer

There is no practical method for decreasing this effect

Question 4

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

Accepted Answer

Perpendicular to the major plane of the discontinuity

Answer

Coplanar with the major plane of the discontinuity

Answer

Parallel to the major plane of the discontinuity

Answer

90 degrees out of phase with the current in the coil

Question 5

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:

Accepted Answer

Lift-off

Answer

Fill factor

Answer

Edge effect

Answer

End effect

Question 6

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:

Accepted Answer

Skin effect

Answer

High-frequency filtration

Answer

Low-frequency filtration

Answer

All of the above

Question 7

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

Accepted Answer

Nonlinearity

Answer

Phase shift

Answer

Lift-off

Answer

Skin effect

Question 8

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

Accepted Answer

Low-pass filter

Answer

Oscillator

Answer

Phase discriminator

Answer

High-pass filter

Question 9

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:

Accepted Answer

Differential

Answer

Absolute

Answer

Laminar

Answer

Flying probes

Question 10

Tubing is generally inspected using:

Accepted Answer

Encircling coils

Answer

U-shaped coils

Answer

Gap coils

Answer

None of the above