Which of the following colors are commonly used for fluorescent magnetic particles?

Fluorescent magnetic particles are specifically designed to enhance visibility when subjected to ultraviolet (UV) light during magnetic particle testing. The most commonly used colors for fluorescent particles are primarily green and yellow. This is because they effectively absorb UV light and emit a bright, visible fluorescent light, allowing for better detection of surface discontinuities in ferromagnetic materials.

Green is particularly advantageous due to its high visibility and the ability to provide contrast against various backgrounds, making it easier for inspectors to identify flaws. Yellow also serves a similar purpose, contributing to the overall effectiveness of fluorescent magnetic particle testing in highlighting defects.

While other colors might be used in different testing contexts, green and yellow are the standard choices for fluorescent magnetic particles because they maximize contrast under UV illumination, ensuring that any potential defects are easily detectable.