QUIZ) ASNT L3 MT 5

81. The coercive force the magnetic material whose hystersis loop is shown in figure.4 is given by the

A. amplitude of flux density B at point 8

B. amplitude of flux density B at point E

C. product of B and H at point B

D. negative value of H at point C

82. On the initial magnetization curve the maximum permeability of the magnetic material is achivevd

A. at the point of maximum slope on curve o-a

B. at the point of maximum slope on curve a-c

C. at point a

D. at the point of maximum slope on curve c-d

83. The effective permeability of the magnetic material would be given by the ratio of B and H at

A. point a to b

B. point b

C. point c

D. point d

84. When demagnetizing small parts is most effective to position them

A. as near as possible to the center of the coil

B. as near as possible to the outside wall of the coil

C. as near as possible to the inside wall of the coil

D. in any of the above positions

85. To be assured that a circularly magnetized part

A. use a field indicator

B. used a good quality pocket compass

C. remagnetize the part with a longitudinal field and then go through the coil

86. L/D ratio where a 5 turn coil will be used to inspect that is 18inch Long and diameter 1.5 inch?

A. 9 B. 12 C. 16.5 D. 3.6

87. In the international system of unit(SI) the unit of magnetic flux density is the

A. Joule B. Weber C. Tesla D. Newton

88. One line flux per square centimeter of area is

A. A measure of a hysteresis loop

B. A measure of line of force

C. the numerical value of one Gauss

D. none of the above

89. The lines of force or flux 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

90. Small part require demagnetization should be

A. loaded in baskets and passed through an AC coil

B. demagnetized after assembly to assure complete demagnetization of the entrre assembly

C. processed through a demagnetization cycle one at a time

D. loaded in a steel basket for better field distribution

91. When the most complete demagnetization available is desired and demagnetization is to be

accomplished by placing the part in a coil energized with AC of progressively decreasing amperage the

following orientation of long axis of the part is most desirable

A. East- West

B. North- South

C. South-West

D. North-East

92. When using DC, an indication is detected. What is the next logical step to determine if the indication

results from a surface or subsurface condition?

A. reinspect using the surge method

B. demagnetize and apply powder

C. reinspect at higher amperage

D. reinspect using AC

93. A cylindrical part is to be tested using circular magnetization. The part has three different diameters

along its length. A rule of thumb for current values for each diameter provides three current levels‘ Which

of the derived current values should be applied first?

A. The highest value

B. The median value

C. The lowest value

D. It does not matter which is applied first

94. The circumference indication is the inside surface at the ring. What type of magnetism is being applied

to the ring?

A. Direct circular

B. Indirect circular

C. Longitudinal

D. Ring should be rotated at least 90 degree

95. The magnetic field is strongest when the

A. magnetizing voltage is flowing

B. magnetizing current is flowing

C. material exhibits high coercive force

D. magnetizing current is not flowing

96. When the skin effect of AC is used and it is important to detect surface defects, alternating current is

used instead of direct current because

A. particle mobility is no longer a factor

B. DC saturates the magnetic particle better than AC

C. the skin effect of AC

D. not at all

97. The most effective MT method for inspection of a large casting is the use of

A. multidirectional magnetization

B. a central conductor

C. prod inspection in two directions

D. direct magnetization

98. Bar magnets exhibit which of the following characteristics?

A. Normally bar magnets have two poles

B. Flux lines within the bar magnet are oriented in a circular configuration

C. There is little or no external magnetic field exhibited by a bar magnet

D. The magnetic field is totally external

99. A group of indications some sharp and some broad and hazy were found on an area of a small-forging

Demagnetization and reinspection eliminated these indications. What was the probable cause?

A. Forging lap

B. Magnetic writing

C. Change in permeability

D. A subsurface variation

100. A seam welded pipe that had the weld ground flush showed broad, fuzzy indications near the toes of

the weld that extended the complete length of the pipe. Which of the following best describes the

probable cause of the indication?

A. Magnetic writing

B. Geometry of the weld

C. Surface crack

D. Permeability change in the base metal at the heat affected zone

 

 

 

 

answer

81	82	83	84	85	86	87	88	89	90
D	A	A	C	C	B	C	C	D	C
91	92	93	94	95	96	97	98	99	100
A	D	C	D	B	C	A	A	B	D