Which transducer type has the same line density for both the near and far field?

Which transducer type has the same line density for both the near and far field?

• A. Phased array
• B. Curved array
• C. Linear array
• D. Annular array

Answer: (C)

Line density is about how many scan lines appear per unit width of the image at a given depth. It depends on how the beams are emitted and spread. A linear array sends parallel beams, so the scan lines stay evenly spaced as depth increases. The spacing between lines doesn’t change from near to far fields, giving the same line density at both depths. Other transducer types—phased, curved, and annular—produce beams that fan out or bend with depth. That spreading or focusing changes how many lines fit into a given width as you go deeper, so the line density differs between near and far fields. So, the linear array is the one with the same line density in near and far fields.

Line density is about how many scan lines appear per unit width of the image at a given depth. It depends on how the beams are emitted and spread.

A linear array sends parallel beams, so the scan lines stay evenly spaced as depth increases. The spacing between lines doesn’t change from near to far fields, giving the same line density at both depths.

Other transducer types—phased, curved, and annular—produce beams that fan out or bend with depth. That spreading or focusing changes how many lines fit into a given width as you go deeper, so the line density differs between near and far fields.

So, the linear array is the one with the same line density in near and far fields.