What happens to an eddy current test coil's magnetic field intensity as the distance outside the coil increases?

In eddy current testing, the magnetic field generated by the test coil behaves in a specific manner as you move further away from the coil. As the distance from the coil increases, the intensity of the magnetic field diminishes. This phenomenon occurs due to the geometric spreading of the magnetic field lines as they extend outward from the coil.

Moreover, within the coil, the magnetic field does not remain uniform; it varies across the diameter due to the nature of how the eddy currents are induced in the test material. The intensity is highest at the center of the coil and decreases toward the edges. Therefore, the correct assertion here is that as the distance outside the coil increases, the magnetic field decreases and also varies across the diameter inside the coil, reflecting both the diminishing strength of the field with distance and the variation in field intensity within the coil itself.