Some Investigations into the Velocity of Sound at Ultra-sonic Frequencies Using Quartz Oscillators

Abstract

The velocity of sound at ultra-sonic frequencies is measured over a frequency range from 40 to 216 kilocycles per second using quartz crystals as sound oscillators. The emitted sound is reflected back upon the source and as its phase changes the plate current of the quartz oscillator goes through a series of maximum values. The distance moved by the sound reflector between these maxima is a half wave-length of the emitted sound.