UBC Theses and Dissertations
Velocity of sound in solid iodine Leith, Marshall Montgomery
The pulse technique was employed to measure velocities of longitudinal and transverse mechanical waves in solid iodine at ultrasonic frequencies. Pulses were produced and their echoes displayed by a Sperry Ultrasonic Attenuator Comparator. Transducers for generating the waves were: longitudinal waves, X-cut quartz crystals of 5 and 12 Mcs.; transverse waves, Y-cut quartz crystal of. 5 Mcs. For longitudinal measurements the sample was immersed in baths of liquid helium, liquid nitrogen, solid carbon dioxide, ice, ambient room temperature, and boiling water. No dispersion was found. Four samples were used, but as iodine is anisotropic in many of its physical properties most attention was paid to two amorphous samples which were thought to give representative average values of the properties of iodine. From the values of longitudinal velocity, Young's modulus was calculated. Transverse velocity measurements were made in baths of liquid helium, liquid nitrogen, carbon dioxide, and ambient room temperature. The shear, modulus was determined from the transverse velocity; compressibility was found from Young's modulus and the shear modulus. All these quantities behave much as would be expected of a solid material. The Debye characteristic temperature calculated from the longitudinal and transverse velocities was compared with values calculated from specific heat data and Lindemann melting point formula.
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