List of top Basic Engineering and Science Questions on Ultrasonics

A system has poles at 0.01 Hz, 1 Hz and 80 Hz, zeros at 5 Hz, 100 Hz, and 200 Hz. The approximate phase of the system response at 20 Hz is

The block diagram for a control system is shown below: for a unit step change in the set point, \( R(s) \), the steady-state offset in the output \( Y(s) \) is 

The unit of filter medium resistance is
What is the near field length \(N\) that can be calculated from the relation (if \(D\) is the diameter of the transducer and \(\lambda\) is the wavelength of sound in the material)?
What is the near field length \(N\) that can be calculated from the relation (if \(D\) is the diameter of the transducer and \(\lambda\) is the wavelength of sound in the material)?