Magnetic Particle Inspection Level 2 Practice Exam

The lines of force that form a path around a crack in a ring magnet are known as what?

1. Magnetic lines

2. Leakage flux

3. Field strength

4. Longitudinal field

The correct answer is: Leakage flux

The lines of force that create a path around a crack in a ring magnet are referred to as leakage flux. When a magnetic field is created around a magnet, such as a ring magnet, the magnetic lines of force normally travel in closed loops from one pole of the magnet to the other. However, if there is a discontinuity like a crack, the lines of force will tend to distort and leak away from their intended path. This leakage indicates the presence of a defect such as a crack. Leakage flux is significant in magnetic particle inspection because it is through this displacement of magnetic lines that particles can be attracted and collect at the area of the defect, forming a visible indication of the crack. In practical terms, the presence of leakage flux can provide visual evidence of surface or near-surface discontinuities in ferromagnetic materials, making it a key principle in nondestructive testing techniques. Understanding this concept is critical in interpreting magnetic particle test results, as the focus is on the ability of the magnetic field to indicate abnormalities in tested materials.