A non-contact piezoelectric level sensor made from Sonox P5 (see CeramTech data sheetsLinks to an external site.) is used to monitor the amount of sugar syrup left in a storage silo at a cake factory (see image below). The piezoelectric transceiver (combining the function of an emitter and receiver) is a 20mm diameter, 1.5mm thick disc of the piezoelectric ceramic with metal contacts on the upper and lower surfaces (the material is poled via these contacts and the emitted and detected pressure pulses are via these large faces). The piezoelectric transceiver is located in the top of the silo and measures the liquid level by bouncing sound pulses off the liquid below. The electronics in the transceiver measures the time delay between emitting pressure (sound) pulses and detecting the returning echo that is reflected off the liquid surface. A short delay indicates that the silo is full, while a long delay indicates that liquid level is near the bottom of the silo. One challenge with this type of level sensor is the attenuation of the pressure pulses as they travel from the transducer, to the surface of the liquid and then back to the transducer. It is therefore useful to consider how much voltage would be produced by the sensor for a given sound intensity of returning pulse. If we assume that a pressure pulse returning from a near empty silo induces a stress of 16.5 Pa in the piezoelectric, what voltage signal would be expect to see? Please state your answer in millivolts (mV) to two decimal places.

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A non-contact piezoelectric level sensor made from Sonox R5 (see CeramTech data sheets ) is used to monitor the amount of sugar syrup left in a storage silo at a cake factory (see image below). The piezoelectric transceiver (combining the function of an emitter and receiver) is a 20mm diameter, 1.5mm thick disc of the piezoelectric ceramic with metal contacts on the upper and lower surfaces (the material is poled via these contacts and the emitted and detected pressure pulses are via these large faces). The piezoelectric transceiver is located in the top of the silo and measures the liquid level by bouncing sound pulses off the liquid below. The electronics in the transceiver measures the time delay between emitting pressure (sound) pulses and detecting the returning echo that is reflected off the liquid surface. A short delay indicates that the silo is full, whil a long delay indicates that liquid level is near the bottom of the silo. One challenge with this type of level sensor is the attenuation of the pressure pulses as they travel from the transducer, to the surface of the liquid and then back to the transducer. It is therefore useful to consider how much voltage would be produced by the sensor for a given sound intensity of returning pulse. If we assume that a pressure pulse returning from a near empty silo induces a stress of 16.5 Pa in the piezoelectric, what voltage signal would be expect to see? Please state your answer in millivolts (mV) to two decimal places