How does reverse piezoelectricity work?

How does reverse piezoelectricity work?

• A. Crystal vibrates -> sound waves -> vibrate tissues -> friction -> heat (voltage passes through crystal)
• B. Crystal stores energy -> releases as heat
• C. Crystal emits magnetic fields that warm tissue
• D. Crystal conducts electricity without physical movement

Answer: (A)

Reverse piezoelectricity is the conversion of electrical energy into mechanical vibration. When an electric signal drives a piezoelectric crystal, the crystal vibrates at a high frequency and emits ultrasound waves. Those waves propagate into the tissue, causing microscopic tissue motion; the tissue’s internal friction and absorption convert part of that mechanical energy into heat. So the sequence—electric energy makes the crystal vibrate, it emits sound waves, those waves vibrate tissue, and friction turns some of that energy into heat—is the essence of how reverse piezoelectricity works. That’s why this option is correct. The other ideas don’t describe the electric-to-mechanical-to-acoustic conversion that produces ultrasound.

Reverse piezoelectricity is the conversion of electrical energy into mechanical vibration. When an electric signal drives a piezoelectric crystal, the crystal vibrates at a high frequency and emits ultrasound waves. Those waves propagate into the tissue, causing microscopic tissue motion; the tissue’s internal friction and absorption convert part of that mechanical energy into heat. So the sequence—electric energy makes the crystal vibrate, it emits sound waves, those waves vibrate tissue, and friction turns some of that energy into heat—is the essence of how reverse piezoelectricity works. That’s why this option is correct. The other ideas don’t describe the electric-to-mechanical-to-acoustic conversion that produces ultrasound.