Ultrasonic waves transmitted into and received from the test material in the form of repetitive bursts of acoustic energy is known as?

The correct choice is based on the principle of how ultrasonic waves are used in nondestructive testing. In pulse-echo testing, ultrasonic waves are sent into the material in short bursts, known as pulses. These pulses travel through the material, and when they encounter a boundary, such as a flaw or a change in material properties, some of the waves are reflected back to the transducer. The transducer then receives these reflected waves, allowing an operator to analyze the data to determine the presence and characteristics of any flaws.

Pulse-echo testing is widely used because it enables the detection of discontinuities within the material and offers information about their depth and size based on the time it takes for the echoes to return. The method is efficient, providing a clear and manageable way to assess material integrity without requiring direct access to both surfaces of the test material.

The other testing methods, while related to ultrasonic techniques, do not specifically involve this burst transmission and reception of energy in the same way. Continuous wave testing involves sending a continuous signal rather than discrete pulses, which makes it different from pulse-echo testing. Reflection testing is too broad and does not distinctly refer to the same method used in pulse-echo. Resonance testing is a specific technique that assesses material properties