In Eddy Current Testing, what does a change in amplitude indicate?

A change in amplitude during Eddy Current Testing can indicate a change in material properties or the presence of a defect. This is because the amplitude of the induced eddy currents is influenced by factors such as the conductivity, permeability, and thickness of the material being tested. When a defect, such as a crack or corrosion, is present in the material, it can alter the flow of eddy currents, resulting in a noticeable change in the amplitude of the signal received.

This phenomenon is critical for diagnostic purposes, as fluctuations in amplitude can help distinguish between different types of materials, the integrity of those materials, and any potential issues within them. Therefore, understanding these changes in amplitude is essential for accurately interpreting the results of Eddy Current Testing and effectively identifying defects.

While changes in environmental conditions or variations in test setups may also influence the results, those factors would more commonly affect other characteristics of the signal rather than amplitude specifically indicating defects. Thus, option B accurately captures the significance of amplitude changes during testing.