Which statement differentiates a phased array transducer from a linear array?

• A. Linear array steers electronically with a small footprint; Phased array uses a fixed rectangular aperture.
• B. Phased array steers electronically with a small footprint; Linear array uses a fixed rectangular aperture.
• C. Phased array uses a curved aperture; Linear array has a fixed rectangular aperture.
• D. Endocavity transducers are used externally.

Answer: (C)

The thing being tested is how beam steering and the physical aperture shape differ between these transducers. A phased array uses many small elements and steers the beam electronically by applying precise time delays across them. This arrangement and steering approach create a curved, fan-shaped aperture, which is why images from phased arrays are typically sector-like. A linear array, on the other hand, has a fixed rectangular arrangement of elements, and its aperture remains flat and rectangular; scanning across it preserves that rectangular geometry. So the defining difference is curved aperture in the phased array versus fixed rectangular aperture in the linear array.