ET ASNT LEVEL 2 QUESTIONS WITH CORRECT ANSWERS

A method of minimizing the effect of indications caused by gradual dimensional changes while retaining the indications caused by discontinuities is to: 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 CORRECT ANSWER a. include a high-pass filter in the eddy current test equipment Which of the following methods may be used to improve the signal-to-noise ratio of an eddy current test system? a. filtering or differentiation b. phase discrimination c. integration d. all of the above CORRECT ANSWER d. all of the above In order to decrease the effect on conductivity readings due to variations in test part thickness: 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 CORRECT ANSWER a. the test frequency should be increased When testing by the eddy current method, discontinuities will be most easily detected when the eddy currents are: 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 CORRECT ANSWER b. perpendicular to the major plane of the discontinuity 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: a. fill factor b. edge effect c. end effect d. lift-off CORRECT ANSWER d. lift-off 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: