Focusing improves lateral resolution because it ______ beam width.

Focusing improves lateral resolution because it ______ beam width.

• A. Decreases beam width
• B. Increases beam width
• C. Curves the beam
• D. Increases amplitude

Answer: (A)

Focusing narrows the beam width in the focal region, and lateral resolution depends on how wide the beam is at that depth. When the beam is narrower, two reflectors that are close together side-by-side can produce distinct echoes rather than a single blurred response, so the ability to distinguish those structures improves. Energy is concentrated at the focus, increasing intensity there, but the key factor for lateral resolution is the reduced beam width.

Focusing narrows the beam width in the focal region, and lateral resolution depends on how wide the beam is at that depth. When the beam is narrower, two reflectors that are close together side-by-side can produce distinct echoes rather than a single blurred response, so the ability to distinguish those structures improves. Energy is concentrated at the focus, increasing intensity there, but the key factor for lateral resolution is the reduced beam width.