On an A-scan display, what represents the intensity of a reflected beam?

• A. Signal amplitude
• B. Echo pulse width
• C. Horizontal screen location
• D. Signal brightness

Answer: (A)

In an A-scan display, the vertical axis shows how strong each echo is, so the intensity of a reflected beam is represented by the signal amplitude. A stronger reflection returns more energy, yielding a taller spike on the trace, which visually encodes greater amplitude and thus higher intensity. The horizontal axis represents time of flight (depth), so it tells where the reflector is, not how strong it is. Echo width would relate to the duration of the received signal, not its strength, and brightness isn't the way amplitude is displayed on an A-scan.