When testing tubing with an inside diameter coil, where do most eddy currents flow?

When testing tubing with an inside diameter coil, most eddy currents flow around the inside diameter of the tubing. This is due to the design of the coil and how it interacts with the conductive material of the tubing. The inside diameter coil generates a magnetic field that induces currents in the tubing. The resulting eddy currents are primarily concentrated in the areas closest to the inside diameter where the magnetic field is strongest.

This arrangement is particularly effective for detecting flaws or variations in wall thickness along the inner surface of the tubing, as the induced currents will respond more significantly to changes in material properties or geometry in that region. By focusing on the inside diameter, technicians can acquire more accurate readings and insights into the condition of the tubing being inspected.

In this scenario, the flowing eddy currents enhance the detection of possible discontinuities or defects, which is essential for ensuring the integrity and reliability of the tubing in its application. The other options do not accurately represent the nature of eddy current flow in this specific setup with an inside diameter coil.