UPSC 2017 CDS II GK Paper

Ultrasonic waves are produced by making use of piezoelectric material. In most of the applications, ultrasonic waves are generated by a transducer that includes a piezoelectric crystal that converts electrical energy (electric current) to mechanical energy (sound waves). These sound waves are reflected and return to the transducer as echoes and are converted back to electrical signals by the same transducer or by a separate one