Ultrasonic interferometer is an essential instrument in fields such as materials science, medical diagnostics, and industrial testing. Its ability to measure the velocity of sound in various materials provides invaluable insights into the physical properties of those materials, contributing to advancements in research and technology. By using sound waves and interference patterns, it enables scientists and engineers to gather accurate data, leading to improved product quality, better understanding of material behavior, and development of new technologies. The principle used in the measurement of velocity is based on the accurate determination of the wavelength  in the medium. Ultrasonic waves of known frequency (f) are produced by a quartz crystal fixed at the bottom of the cell. These waves are reflected by a movable metallic plate kept parallel to the quartz crystal.