Experiment was done by using an oscilloscope and a piezoelectric transducer to generate ultrasonic sound waves. We had to move the transmitter whilst receiver remains constant on a angled 1 meter track or vice versa.
As you change the separation between the transmitter and the receiver, one signal changes in size and the other remains the same. Which one of these signals changes? What causes this change in amplitude? Why does one signal remain the same?
And that is the question I don't understand.
I believe signal generated with a piezoelectric transducer was fed to the oscilloscope with the signal collected by the sensor (receiver). And the one collected with the sensor was the one that changed. (I don't know why. Maybe because of energy lost?)
Also I have used this formula A = D/f to calculated the amplitude. 5.0X10^-6 m (5.0X10^-6 = 0.18 / 35950) Does this sound reasonable? With this amplitude I believe its enough for the signal to bounce off the receiver and transmitter and cause constructive and destructive interference. (Approx. receiver radius of 1.5 cm, transmitter 1.5 cm+)