The amount of energy reflected from a discontinuity depends on which factors?

• A. Ambient humidity
• B. Operator skill
• C. Discontinuity size, shape and orientation
• D. Color of the test object

Answer: (C)

The amount of energy that reflects from a discontinuity is governed by the geometry of the defect as it presents to the ultrasonic beam. A larger cross-section intercepts more of the sound wave, so more energy is reflected back to the transducer. The shape matters because flat, planar features can reflect energy efficiently when aligned with the beam, while curved or irregular shapes tend to scatter energy and reduce the back echo. Orientation is crucial: when the discontinuity is perpendicular to the incident beam, the reflection is strongest; when it’s tilted or edge-on, much of the energy is directed away or into other directions, yielding a weaker back signal. External factors like ambient humidity or the color of the object don’t affect the reflection physics, and while operator technique affects interpretation, it doesn’t change how much energy is reflected by the discontinuity itself.