What primarily represents the impedance of a test coil?

The impedance of a test coil in Eddy Current Testing is primarily represented by the combination of inductive reactance and resistance. Inductive reactance arises from the coil's inductance, which affects how the coil responds to alternating current (AC). When an AC signal is applied to the coil, the magnetic field generated by the coil reacts with the conductive material being tested, causing eddy currents to flow within that material. The inductive reactance plays a crucial role in determining how much current flows through the coil based on the frequency of the applied signal and the geometry of the coil.

Resistance, on the other hand, represents the real part of the coil's impedance, accounting for energy losses within the coil due to heat. This resistance is particularly important because it affects the overall efficiency of the coil in generating a response to the test material. When evaluating the performance of the test coil, both the inductive reactance (which represents the coil's opposition to changes in current due to induction) and the resistance (which accounts for energy loss) are critical in establishing the total impedance.

In summary, the correct answer illustrates that the impedance encompasses both the inductive reactance, which is influenced by the frequency and the coil's design, and the resistance, which