QUIZ) ASNT L3 MT 1

1. The magnetic principle underlying circular magnetization with a central conductor is based on the fact that

A. Circular(eddy) currents are induced by magnetic flux

B. the "Hall effect" is applied in finding the "constant" for the L/D ratio

C. there is a circular magnetic field surrounding any electrical conductor

D. the direction of the magnetic flux lines is determined by the direction of the arrow

2. If the orientation of crack-like flaws in a part is unknown, the greatest ability of detection of such

flaws would result from use of

A. an eccentric solenoid

B. an alternating radial field

C. a rotating vector field

D. a transverse current

3. A field indicator is used to best advantage in comparing the external strength of the magnetic field in

parts that are

A. longitudinally magnetized

B. magnetized in a head shot

C. circularly magnetized

D. multi-directional magnetized

4. A closed lipped indication easily detected by using alternating current and propagates based on cyclically

applied stress

A. fatigue crack

B. creep crack

C. stress corrosion

D. hydrogen crack

5. Which of the following discontinuities would be least likely to be detected when performing a dry

magnetic particle production examination of a weldment?

A. Tightly closed surface cracks

B. Porosity

C. undercutting

D. shallow(1/16 inch deep or less) slag inclusions

6. Current in a coil abruptly terminated while using three-phase full rectified AC is referred to as the:

A. vector field technique

B. quick break technique

C. coil applied technique

D. alternating current technique

7. At temperatures greater than half the melting point and at stresses below the yield strength of the material

deformation can occur by the action of grains gradually separating. This deformation of failure mechanism

is referred to as

A. fatigue cracking

B. creep cracking

C. stress corrosion

D. hydrogen cracking

8. The reason for using a filter with the UV radiation source is

A. to protect the inspector's eye

B. to protect the black light from affecting the magnetic field

C. to attenuate excessive UV-radiation

D. to prevent visible light from the radiation

9. Multidirectional magnetization has a distinct advantage over other magnetization techniques because of

the capability to detect very small discontinuities. The magnetic field changes it’s direction in the rhythm

of the alternate frequency of the current application becoming alternately perpendicular to certain cracks.

Which sequence of operation would be correct for this application?

A. Apply magnetizing current, shunt off current, apply testing medium, perform inspection

B. Apply testing medium, apply magnetizing current, perform inspection, shut off current

C. Apply magnetizing current and testing medium while simultaneously performing inspection

D. Apply magnetizing current and testing medium, shut off current, perform inspection with residual magnetism

10. The settling test used in wet fluorescent magnetic particle inspection cannot be used to detect

A. excessive particle in suspension

B. excessive fluorescent backgroud in the vehicle

C. excessive particle contamination

D. extraneous oil contamination

11. When using the dry continuous method of magnetic particle testing, the best results are obtained when

the particles are

A. applied before the current is activated

B. applied after the current is removed

C. applied during the clearing process

D. applied during the application of current

12. A magnetic particle suspension with a broad distribution of grain sizes is used in a closed circuit to test

a large number of small forgings for small crack(bench). During an extended period of use, the bath

strength and the average grain size would change as follow

A. strength:lower, size:larger

B. strength:lower, size:smaller

C. strength:higher, size:smaller

D. strength:higher, size‘:larger

13. The Hall element sensor is made from crystals of semiconductor material. When a current is passed

through the semiconductor material a voltage is developed across two of the faces of the crystal. Which

describes the relationship between the voltage and strength of the magnetic field?

A. The voltage is proportional to the strength of the magnetic field

B. The voltage is indirect proportional to the strength of the magnetic field

C. The voltage is proportional to the magnetic field and indirectly proportional to the electronic change in

coulombs

D. The voltage variations associated with semiconductor material are not adequate for Hall Element sensors

14. When demagnetizing a part the operator must

A. lightly hammer the part

B. take into account the effect of terrestrial fields

C. use the loop method on large parts

D. be familiar with the principles involved and the degree of demagnetization required

15. The magnetic field present in a ring magnet is circular in nature. The detectability of this field is difficult

because

A. it is limited to the immediate outside diameter of the ring

B. the molecular alignment does not create a strong enough field to be detected

C. there is no leakage field at external poles

D. a natural ring magnet does not conform to the domain theory of magnetism

16. The major purpose of the braid copper pads in head shot contact areas is to

A. increase contact area and reduce current density at the contacts

B. more firmly hold the parts in position

C. help heat the parts, thereby facilitating magnetic induction

D. permit better current induction when AC is used

17. When performing a circular MT inspection on a hollow tubular structure, a central conductor is preferred

over directly passing the current through the tube because

A. direct electcrical contact is not made with the test object, there by eliminating the liklihood of buring

B. the central conductor only magnetizes the outside of the test piece, where as the direct contact magnetic

the inside and out side

C. the direct contact with the tubular structure is only applicable for parts under 18" long

D. the central conductor applies a circular and longitudinal to the test piece at the same time

18. During the magnetic particle examination on the edge of a steel plate, a linear terraced or step-like

indication in the base method is found adjacent to a fillet welded support. What is the discontinuity

A. lack of fusion

B. lamellar tearing

C. undercut

D. hot crack

19. Which of the following will give an indication of the direction in testing of magnetic field

A. Ketos ring

B. Circle shims

C. Ammeter

D. Voltmeter

20. The field in a section of pipe being magnetized by means of a central conductor is stronger at the

A. ends of the pipe

B. outer surface of the pipe

C. inside surface of the pipe

D. middle of the pipe wall

 

 

 

 

 

answer

1	2	3	4	5	6	7	8	9	10
C	C	A	A	A	B	B	C	C	D
11	12	13	14	15	16	17	18	19	20
D	A	A	D	C	A	A	B	B	C