Non-Destructive Testing (NDT) Practice Test

What occurs as sound beams move further from the transducer?

1. The sound wave increases in speed

2. The sound wave remains consistent

3. The sound beam spreads apart

4. The sound beam gets absorbed

The correct answer is: The sound beam spreads apart

As sound beams travel away from the transducer, they naturally spread apart due to the geometric divergence of the wavefronts. This phenomenon occurs because sound waves emanate from a point source and radiate outward in a spherical pattern. As the distance from the source increases, the energy of the sound wave is distributed over a larger area, resulting in a decrease in intensity per unit area. This spreading of the sound beam is an important aspect to consider in Non-Destructive Testing, as it affects the resolution and sensitivity of the inspection process. Wider beam spread can lead to a loss of detail and the potential for decreased detection of flaws, as the waves become less focused and may overlap with surrounding structures or noise in the material being tested. The other options do not accurately describe what happens to sound beams as they move away from the transducer. The speed of sound in a given medium remains relatively constant, absorption may occur depending on material properties, but is not a primary factor just due to distance from the transducer, and the consistency of the sound wave is impacted by physical factors like spreading, not maintained.