Which UT display shows echo amplitude versus time (depth)?

• A. A-scan
• B. B-scan
• C. C-scan
• D. D-scan

Answer: (A)

Echo amplitude versus time (depth) is shown on an A-scan. When you send a pulse and listen for echoes, each reflection appears as a spike, and the spike’s height corresponds to the echo’s amplitude. The horizontal axis represents time after emission, and with the material’s sound speed you convert that time into depth. This display directly ties how strong an echo is to how far away its reflector is, which is why it’s the go-to view for sizing features and detect flaws. Other displays show different things: a B-scan builds a 2D image by combining many time traces along a scan, a C-scan provides a plan view at a fixed depth, and a D-scan presents time-based data in a different format. The question’s description matches the A-scan most closely.