Magnetic Particle Inspection Level 1 Practice Exam

Why can some small discontinuities be visible during magnetic particle testing without magnification?

1. They create sound waves detectable by the human ear

2. They disrupt the magnetic field allowing particles to form a visual indicator

3. They emit light when exposed to UV radiation

4. They can be felt through touch

The correct answer is: They disrupt the magnetic field allowing particles to form a visual indicator

The reason some small discontinuities can be visible during magnetic particle testing without the need for magnification is that they disrupt the magnetic field in a way that allows the magnetic particles to accumulate and create a visible indication. When the magnetic field is applied, it flows through the material. If there are any discontinuities, such as cracks or other defects, these disrupt the flow of the magnetic field. As a result of this disruption, magnetic particles, which are coated with a fluorescent dye or are dry, will congregate at the site of the discontinuity. This forms a visible indication that can be seen with the naked eye, enabling inspectors to identify and analyze defects effectively without having to rely on magnification. This characteristic is one of the key advantages of magnetic particle testing, as it allows for the detection of smaller flaws in contrast to other methods that may require more sophisticated equipment.