Which design feature is characteristic of convex sequential arrays?

• A. All crystals fire at once
• B. None of the crystals fire
• C. Some but not all crystals fire
• D. Beams are parallel

Answer: (C)

Convex sequential arrays generate the ultrasound beam by energizing small groups of crystals in sequence along the curved surface. Because only a portion of the total crystals is active at any moment, the emitted wavefront is formed as the active group steps through the array, creating a curved, fan-shaped beam that sweeps across the field. That’s why the description “some but not all crystals fire” best fits this design.

The other ideas don’t match the pattern of operation: firing all crystals at once would produce a different, less controllable beam, and the curved geometry prevents the beam from being parallel.