In a test where the transducer is angled to the inspection surface, what equals the angle of incidence?

In the context of ultrasonic testing, when a transducer is angled relative to the inspection surface, the angle of incidence is defined as the angle at which the ultrasound beam strikes the surface. According to the laws of reflection, the angle of incidence is equal to the angle of reflection. This means that if a transducer sends an ultrasonic wave at a specific angle to an interface, the wave will reflect off that interface at the same angle, maintaining the principle that angles are measured from a straight line perpendicular to the surface (normal line).

Understanding this relationship is crucial in NDT because it helps in interpreting the results when analyzing reflected waves, especially when dealing with flaws or interfaces. The angles involved play a significant role in determining how sound waves propagate through materials and how they are reflected, which directly influences the accuracy and reliability of test results.

In contrast, the angle of refraction pertains to the bending of the wave as it passes into another medium, which is governed by Snell's Law, while the angle of deviation does not directly relate to reflection or refraction in this context. Angle of diffraction involves the spreading of waves when they encounter an obstacle or slit, which is also not related to incidence or reflection at an interface in standard ultrasonic testing scenarios.