In magnetic particle inspection, what does a flaw perpendicular to the magnetic field flux lines cause?

In magnetic particle inspection, a flaw that is perpendicular to the magnetic field flux lines will create a significant disruption in the magnetic field. This phenomenon occurs because the magnetic field lines are altered as they encounter the discontinuity, which can be a crack, void, or other defect. The introduction of a flaw that crosses these field lines will cause the lines to diverge, leading to an increased concentration of magnetic flux at the edges of the flaw.

This disruption is critical for the detection of defects; it allows the magnetic particles that have been applied to the surface to accumulate at the site of the discontinuity, making the flaw visible under appropriate lighting conditions. Accurate detection of such flaws is essential in various industries to ensure the integrity and reliability of components and structures.

The other choices do not accurately capture the behavior of magnetic fields in relation to perpendicular flaws, as they either downplay the disruption caused or suggest a lack of effect entirely.