An ultrasonic testing instrument that displays pulses representing the magnitude of reflected ultrasound as a function of time or depth of metal is said to contain:

• A. A continuous wave display
• B. An A scan presentation
• C. A B scan presentation
• D. A C scan presentation

Answer: (B)

The display described is a one-dimensional time-to-depth profile. In pulsed ultrasonic testing, each echo from a reflector appears as a spike whose horizontal position corresponds to the time of flight (which is converted to depth) and whose height reflects the echo amplitude. This simple, single-line display of amplitude versus time (or depth) is known as an A-scan presentation. It provides precise depth information along a single line of sight.

A continuous-wave display wouldn’t give range information because there’s no pulsed time-of-flight to measure. A B-scan, by contrast, compiles many A-scan lines as the probe is swept to form a two-dimensional image, and a C-scan presents a plan-view map at a fixed depth.