MMET 402 EXAM 1 QUESTIONS WITH
CORRECT ANSWERS
The main sensing element of an eddy current probe is a _____. - Answer- Winding coil
What type of discontinuities is the target for ET inspection? - Answer- Surface (including
near surface)
For ET inspection, the test objects have to be: - Answer- Electric conductors
For ET inspection, increasing the probe frequency will result in: - Answer- Decreasing
the depth of penetration of the eddy current
What type of current is used to operate the ET probe to induce the eddy currents in the
test object? - Answer- High frequency AC (1 kHz - 1 MHz)
The skin depth or the standard depth of penetration of the eddy current induced in a test
object is the depth which its density has decreased to ______ of its maximum value
which occurs at the surface of the test object. - Answer- 1/e
The effective depth of penetration of the eddy current is the depth at which the eddy
current density (word that starts with "d") of surface density and reaches the limit of its
flaw detectability. - Answer- 5%
The effective range of an eddy current inspection is equal to _______ times the skin
depth. - Answer- 3
Which type of penetrant is most sensitive? - Answer- Type IV
Liquid penetration testing is a nondestructive test that can be used for - Answer-
Locating discontinuities open to the surface
Writing ability of a penetrant is measured by its - Answer- Contact angle
Which of the following is generally the more acceptable method for cleaning parts prior
to penetrant testing? - Answer- Vapor degreasing
, Which of the statements below states the danger of sandblasting (without subsequent
chemical etching) for cleaning surfaces to be penetrant tested? - Answer- The
discontinuities may be peened over and closed
Developer is required to - Answer- a. Draw out the penetrant from the discontinuity
b. Provide contrast between the penetrant and the parts background color
->C. ALL OF THE ABOVE <-
Once the surface of the part has been cleaned properly, penetrant can be applied by: -
Answer- Spraying, brushing, and dipping
Post emulsifiable penetrants: - Answer- Require a separate emulsifier to break the
penetrant down and make it water washable
When removal of penetrant from the defect due to overwashing of the part is a concern,
which method should most often be used? - Answer- Fluorescent post emulsifiable
method
Which emulisifier is most sensitive to contact time (emulsification time) when applied to
the parts surface? - Answer- Lipophilic emulsifier
Which type of penetrant is a fluorescent penetrant? - Answer- Type I
What is an advantage of visible dye penetrants over fluorescent penetrants? - Answer-
Visible dye penetrants do not require ultraviolet light
Which of the following discontinuities would be impossible to detect using a liquid
penetrant test? - Answer- Nonmetallic internal inclusions
Which of the following physical properties, more than any other, determines what makes
a material a good penetrant? - Answer- No one single property determines if a material
will or will not be a good penetrant
PT can be used to test most materials provided the surface of the part is: - Answer- Is
not extremally rough or porous
The total time the penetrant is in contact with the part surface is called the: - Answer-
Penetrant dwell time
All of the following parts can be tested by the liquid penetrant method except: - Answer-
A sintered brass component
A part made from porous plastic material
The speed with which a penetrant penetrants a surface flaw is influenced to the greatest
extent by which of the following properties? - Answer- Capillary action
CORRECT ANSWERS
The main sensing element of an eddy current probe is a _____. - Answer- Winding coil
What type of discontinuities is the target for ET inspection? - Answer- Surface (including
near surface)
For ET inspection, the test objects have to be: - Answer- Electric conductors
For ET inspection, increasing the probe frequency will result in: - Answer- Decreasing
the depth of penetration of the eddy current
What type of current is used to operate the ET probe to induce the eddy currents in the
test object? - Answer- High frequency AC (1 kHz - 1 MHz)
The skin depth or the standard depth of penetration of the eddy current induced in a test
object is the depth which its density has decreased to ______ of its maximum value
which occurs at the surface of the test object. - Answer- 1/e
The effective depth of penetration of the eddy current is the depth at which the eddy
current density (word that starts with "d") of surface density and reaches the limit of its
flaw detectability. - Answer- 5%
The effective range of an eddy current inspection is equal to _______ times the skin
depth. - Answer- 3
Which type of penetrant is most sensitive? - Answer- Type IV
Liquid penetration testing is a nondestructive test that can be used for - Answer-
Locating discontinuities open to the surface
Writing ability of a penetrant is measured by its - Answer- Contact angle
Which of the following is generally the more acceptable method for cleaning parts prior
to penetrant testing? - Answer- Vapor degreasing
, Which of the statements below states the danger of sandblasting (without subsequent
chemical etching) for cleaning surfaces to be penetrant tested? - Answer- The
discontinuities may be peened over and closed
Developer is required to - Answer- a. Draw out the penetrant from the discontinuity
b. Provide contrast between the penetrant and the parts background color
->C. ALL OF THE ABOVE <-
Once the surface of the part has been cleaned properly, penetrant can be applied by: -
Answer- Spraying, brushing, and dipping
Post emulsifiable penetrants: - Answer- Require a separate emulsifier to break the
penetrant down and make it water washable
When removal of penetrant from the defect due to overwashing of the part is a concern,
which method should most often be used? - Answer- Fluorescent post emulsifiable
method
Which emulisifier is most sensitive to contact time (emulsification time) when applied to
the parts surface? - Answer- Lipophilic emulsifier
Which type of penetrant is a fluorescent penetrant? - Answer- Type I
What is an advantage of visible dye penetrants over fluorescent penetrants? - Answer-
Visible dye penetrants do not require ultraviolet light
Which of the following discontinuities would be impossible to detect using a liquid
penetrant test? - Answer- Nonmetallic internal inclusions
Which of the following physical properties, more than any other, determines what makes
a material a good penetrant? - Answer- No one single property determines if a material
will or will not be a good penetrant
PT can be used to test most materials provided the surface of the part is: - Answer- Is
not extremally rough or porous
The total time the penetrant is in contact with the part surface is called the: - Answer-
Penetrant dwell time
All of the following parts can be tested by the liquid penetrant method except: - Answer-
A sintered brass component
A part made from porous plastic material
The speed with which a penetrant penetrants a surface flaw is influenced to the greatest
extent by which of the following properties? - Answer- Capillary action
