Which statement is true about convex arrays?

Which statement is true about convex arrays?

• A. Beams are parallel
• B. Crystals widths are variable
• C. Only one crystal is active
• D. Beams are not parallel

Answer: (D)

The main idea here is that the geometry of a convex (curvilinear) array causes the emitted beams to diverge rather than stay parallel. In a convex array, the active elements line a curved surface, so the direction normal to each element varies along the aperture. When those waves combine, the resulting beam fans out. That means beams are not parallel, which is the defining feature of convex arrays. This is why the statement about beams not being parallel is the best choice. If beams were parallel, you’d be describing a linear, not a convex, arrangement. The idea that only one crystal is active doesn’t fit a convex array, which relies on many elements to form and steer the beam. The notion that crystal widths are variable isn’t what characterizes convex geometry.

The main idea here is that the geometry of a convex (curvilinear) array causes the emitted beams to diverge rather than stay parallel. In a convex array, the active elements line a curved surface, so the direction normal to each element varies along the aperture. When those waves combine, the resulting beam fans out. That means beams are not parallel, which is the defining feature of convex arrays.

This is why the statement about beams not being parallel is the best choice. If beams were parallel, you’d be describing a linear, not a convex, arrangement. The idea that only one crystal is active doesn’t fit a convex array, which relies on many elements to form and steer the beam. The notion that crystal widths are variable isn’t what characterizes convex geometry.