MPI Level II Questions (Part 1)

The primary difference between magnetic particle testing and other methods of testing using magnetics, such as electromagnetic resonance, electron paramagnetic resonance and eddy current testing is

A) intensity of field used

B) frequency of field oscillation

C) mono-pole versus bi-pole magnetics

D) none of the above

Two long conductors (wires) are placed parallel and near to each other. When current flows in the same direction in both wires there will exist a

A) net repulsive force between the wires

B) net attractive force between the wires

C) neutral zone at the midpoint between the wires

D) zone of cold fusion at the core of the wires

Two long conductors (wires) are placed parallel and near to each other. When current flows in opposite directions in both wires, there will exist a

A) net attractive force between the wires

B) net repulsive force between the wires

C) neutral zone at the mid point between the wires

D) slight increase in gravitons between the wires

Magnetic dipole moment is a

A) vector quantity

B) scalar quantity

C) nuclear phenomenon

D) small unit of time

The magnitude of the magnetic dipole moment is directly proportional to

A) the amount of current in a coil conductor

B) the area of a coil conductor

C) both a and b

D) the ratio of current to coil area

The magnitude of a magnetic induction field at a perpendicular distance 'r' from the centre of a long straight conductor with a current 'I' amperes is

A) proportional to the current 'I'

B) inversely proportional to the distance 'r'

C) both a and b

D) none of the above

When a current is passed through a long circular conductor of radius R such as a wire the maximum magnetic induction field occurs at

A) the centre of the conductor

B) 0.707 R

C) R (ie. The conductor's surface)

1.414R

The most significant factor contributing to a material possessing magnetic properties is

A) the number of neutrons in the nucleus

B) unpaired electrons in the structure

C) the van Allen belts

D) whether ionic or covalent bonding is responsible for the crystal structure

In normal unmagnetized condition, the domains of a ferromagnetic material are

A) randomly aligned

B) alternately aligned as on a checker board

C) non-existent until an external field is applied

D) found only at the curie point

In ferromagnetic materials the ratio of the magnetic induction field to the magnetic field intensity is called the

A) susceptibility

B) permeability

C) permissivity

D) magnetic impedance

The internal magnetic intensity of a specimen brought into an external magnetizing field will always __________ the applied field.

A) be less than

B) equal

C) be greater than

D) reduce

The slope of the virgin magnetization curve at the origin of a hysteresis plot is called the

A) original magnetization

B) flux density

C) permitivity

D) initial permeability

When a ferromagnetic material is placed in an inducting field H, and H is increased until the incremental permeability is simply the free space permeability this point is called the

A) magnetic saturation

B) inflection point

C) reversal point

D) Barkhausen limit

The small jumps in magnetism as a ferromagnetic material is exposed to an increasing induction field are termed

A) incremental permeability

B) Delta M's

C) magnetic scatter

D) Barkhausen jumps

A closed magnetic path through one or more materials is considered a magnetic circuit. As such, it can be considered analogous to an electric circuit, the magnetic equivalent to voltage is

A) reluctance

B) magnetostriction

C) magnetomotance

D) magneto-voltage

Magnetic circuits are equivalent to electric circuits hence have an equivalent equation to Ohm's law, the term equivalent to electrical resistance in magnetics is

A) coercive force

B) reluctance

C) permeability

D) magnetic flux

In a magnetic circuit, which is equivalent to an electric circuit, the magnetic equivalent to electrical current is

A) magnetomotance

B) reluctance

C) permittivity

D) magnetic flux

The ability of the magnetic particle method to detect subsurface defects is not determined by

A) specimen size

B) defect depth

C) defect orientation

D) strength of applied field

Magnetic particle testing makes use of the phenomenon called

A) magnetostriction

B) magnetic-flux-leakage

C) magnetomotive force

D) piezoelectric effect

Which stage of processing can magnetic particle testing be used?

A) Primary production and processing

B) secondary processing or manufacturing

C) in-service

D) all of the above

Which of the following should not be in the list?

A) ingot

B) bloom

C) billet

D) slab

The collection of magnetic particles caught by a leakage field in a magnetic particle test indicates a discontinuity's

A) location

B) shape

C) size and extent

D) all of the above

Very wide surface cracks may not produce a powder pattern because

A) the surface opening is too wide for the particles to bridge

B) detectability is based of the length to width ratio

C) wide cracks are always shallow

D) all of the above

Magnetic particle testing would give best results when used on

A) cast gray iron

B) soft steel

C) hardened steel

D) stainless steel

Which of the following might be considered a disadvantage of magnetic particle testing?

A) speed of operation

B) relative expense

C) need to demagnetize parts

D) detection of shallow defects

Eddy current testing can also be used to detect surface and sub-surface defects on ferromagnetic materials but is usually inferior to magnetic particle testing because of

A) inspection speed

B) requirement of large saturating bias fields

C) depth and size estimations

D) both a and b

The cause of a magnetic particle indication is always a

A) defect

B) surface blemish

C) discontinuity

D) surface breaking crack

The void that occurs at the top centre portion of an ingot is usually called a

A) hole

B) funnel

C) shrink cavity

D) sprue

Segregation is a(n) _________ process discontinuity.

A) inherent

B) primary

C) secondary

Service

Blowholes not welded shut in subsequent rolling processes can result in

A) seams or laminations

B) pipe

C) segregation

D) laps

MPI Level II Questions (Part 1)

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