Easy
The Direction of the Magnetic field induced by eddy currents
Perpendicular
every atom has what three fundamental particles
Electrons Protons Neutrons
The main purpose for spring-loaded eddy current probe coils is to:
To minimize liftoff
The signal observed when the geometrical boundary of a plate approaches the test coil is called:
edge effect.
The permability of air numerical amount
1
What do Electromagnetic testing instruments measure and display ?
Changes in Coil Impedance
The number of magnetic lines of force passing per unit area perpendicular to the direction of a magnetic field
Magnetic Flux
Two coils are wound and electrically connected so that the output of one cancels the other. What sort of arrangement is this?
Differential coil.
The standard depth of penetration is the distance from the surface of the test object to the point where current density is approximately __ of current density at the surface.
37%
the material's opposition to the flow of current.
Resistivity
What are the Three testing techniques that SNT-TC-1A divides electromagnetic testing into?
Remote Field Testing
alternating current field measurement
Eddy current testing
Which of the following methods or techniques can measure the length and depth of a crack in a weldment?
ACFM
An eddy current test coil's total opposition to the flow of alternating current is called:
Impedance
Can easily detect cracks in the formative stage, which normally exhibit well-defined indications.
MFL
How many different categories of eddy current inspection probes are there ?
Then name them!
SURFACE
INTERNAL
ENCIRCLING
What is Michael Faraday credited with discovering?
The effect of electromagnetic induction
what two factors is the strength of the magnetic field dependent on ?
The number of turns in the coil
The magnitude of the current
What is EMF?
The electrical energy derived from mechanical, chemical, or other forms of energy that must be applied across the material to force the electrons to move.
what is IACS
International anneealed copper standard
A useful technique for detecting the wall thickness of thin materials as well as detecting localized discontinuities.
RFT
The connection between electricity and magnetism by observing how a wire connecting the ends of a voltaic battery affected a compass in its vicinity was first observed by:
Hans Orsted.
A reference standard used to ensure that the amplitude and phase characteristics of an ET system do not drift during continuous testing is called a
CALIBRATION STANDARD
All ferromagnetic materials that have been magnetically saturated to suppress permeability variations may retain a certain amount of the magnetization called the
Residual magnetism
Calculate the fill factor for a 2.25 in. encircling coil inspecting a 2.125 in. copper tube.
FF= d^2/D^2
89%
What are the three fundemental properties of material that affect the eddy current induced into the test park.
Conductivity
Permability
Dimensions