Nondestructive Testing (NDT) UT Level I 2025 – 400 Free Practice Questions to Pass the Exam

The interference field near the face of a transducer is correctly referred to as the Fresnel Zone. This zone is characterized by the complex wave patterns that occur as the ultrasound waves propagate from the transducer. The Fresnel Zone is significant because it encompasses the area where constructive and destructive interference of the sound waves takes place, resulting in varying amplitudes of the sound waves being transmitted.

In this region, the sound field is not uniform; instead, it displays distinct patterns of intensity, which can affect the quality of the ultrasonic inspection. Understanding the characteristics of the Fresnel Zone is crucial for interpreting UT measurements accurately, as the sound field behavior differs significantly between this area and the far field, where the sound waves tend to be more coherent and less affected by interference.

Knowing that the Fresnel Zone pertains specifically to the zone of interference close to the transducer helps differentiate it from other terms such as the Near Field, which refers more broadly to the region closest to the transducer without the specific interference considerations of the Fresnel Zone.