Top 1000+ Solved Non Destructive Testing and Evaluation MCQ Questions Answer
Q. Surrounding an electromagnet, the magnetic field is strongest:
a. Immediately after the current ceases to flow
b. While the magnetizing current ceases to flow
c. At the time the magnetic particles are applied to the part
d. Just prior to current reversal
Q. The value of permeability is:
a. A fixed value depending upon the type of material
b. Between 1 and 100 for all ferromagnetic materials
c. Between 0 and 10 for all ferromagnetic materials
d. Dependent upon the amount of magnetizing force necessary to overcome
Q. The flux density of the magnetism induced by a coil is affected by:
a. The coil size
b. The current in the coil
c. The number of turns in the coil
d. All of the above
Q. How many ampere-turns are required to magnetize a part that is 40.6 cm (16 inches)long and 5 cm (2 inches) in diameter?
a. 9000 ampere-turns
b. 5625 ampere-turns
c. 2812 ampere-turns
d. None of the above
Q. The lines of flux or force in a circularly magnetized ferromagnetic bar:
a. Are aligned through the piece from the south to the north pole
b. Are aligned through the piece from the north to the south pole
c. Leave the south pole and enter the north pole
d. Are contained within and around the part
Q. In which magnetizing method is the current passed directly through the part, therebysetting up a magnetic field at right angles to the current flow?
a. Longitudinal magnetization
b. Coil magnetization
c. Central conductor magnetization
d. None of the above
Q. Which of the following is false concerning a magnetic field in and around a hollow conductor as compared to that of a solid conductor of the same outside diameter when both are of the same magnetic material, and when the applied current is the same?
a. The field immediately outside the outer surface of the hollow conductor is greater
b. The field gradient inside the hollow conductor is steeper
c. The fields outside the conductors are the same
d. The fields are the same at the centre
Q. The field in a section of ferromagnetic pipe being magnetized by means of a centralconductor is strongest at the:
a. Ends of the pipe
b. Outer surface of the pipe
c. Inner surface of the pipe
d. The field is uniform at all places
Q. For a 7.6 cm (3 inches) diameter bar how much current is needed to magnetize the barfor the detection of longitudinal discontinuities:
a. 5500 amperes
b. 16500 amperes
c. 1000 amperes
d. 3000 amperes
Q. For detection of longitudinal discontinuities a 7.6 cm (3 inches) diameter bar ismagnetized in:
a. The longitudinal direction
b. The circular direction
c. The clockwise direction
d. None of the above directions
Q. An advantage of AC is that:
a. It is most readily available
b. Equipment can be made lighter
c. It leaves the part demagnetized
d. All of the above
Q. When a magnetic field cuts across a crack:
a. Electrons begin jumping back and forth across the crack
b. The crack begins to heat up
c. Magnetic poles form at the edges of the crack
d. All of the above
Q. A disadvantage of AC current is that it:
a. Cannot be used with dry powder
b. Has poor penetrating power
c. Can only provide low flux densities
d. Cannot be used for residual magnetic particle testing