Transducers may be focused by internal focusing and external focusing.  These are accomplished by

Refraction will not occur at an interface

Which of the following image shapes is produced by a linear sequenced array real-time transducer? 

Which letter corresponds to the matching layer of the transducer in the following image?

Which of the following is an example of a transducer? 

Which of the following is not a component of the time gain compensation (TGC) curve?

Which of the following produces false echoes that are occasionally seen in fluid-filled masses? 

Axial resolution is also known as all of the following except:

An echo that has undergone an attenuation of 3dB will have an intensity that is ______ than its initial intensity.

Beam steering is achieved in a linear phased array by