Ultrasonic Interferometer For Liquids in Delhi
Ultrasonic Interferometer For Liquids in Delhi
Ultrasonic Interferometer For Liquids Using this instrument several Ph.D. Thesis are awarded and innumerable Research papers are published in National & International Journals. Velocity measurement combining with other physical quantities provides information of more than 30 Parameters. For ready reference few Equations are listed here. Few Experiments are also suggested for laboratory purpose. Working Principle The principle used in the measurement of velocity (ν) is based on the accurate determination of the wavelength (λ) 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. If the separation between these two plates is exactly a whole multiple of the sound wavelength, standing waves are formed in the medium. This acoustic resonance gives rise to an electrical reaction on the generator driving the quartz crystal and the anode current of the generator becomes a maximum. If the distance is now increased or decreased, and the variation is exactly one-half wavelength ( λ /2), or multiple of it, anode current becomes maximum. From the knowledge of wavelength ( λ ) the velocity (v) can be obtained by the relation: Velocity = Wavelength x Frequency v = λ x f The Ultrasonic Interferometer consists of the following parts: HIGH FREQUENCY GENERATOR Single and Multi-frequency MEASURING CELL Max. displacement of the reflector : 20 mm Required Quantity of liquid: 10 c.c. Least Count of micrometer: 0.01mm/0.001 mm SHIELDED CABLE Impedance : 50 O Optional: If the variation in the velocity with temperature is to be studied, water at various desired constant temperatures is made to circulate through the double walled jacket of the cell with external circulating water bath. A number of parameters related to ultrasonic velocity are: Compressibility Effective Debye Temperature Excess Enthalpy Hydrogen Bonding Intermolecular Free Length Solvation Number/ Hydration Number Vander Wall's Constant Rao's Constant Wada Constant Molecular Interaction Proton Relaxation Rate Relative Association Relaxation Time and Relaxation Strength Acoustic Impedance Stacking Constant Space Filling Factor Cohesive Energy Barrier Latent Heat Of Vaporization Specific Heat Ratio Miscibility and Compatibility of Blends and many more
Mittal Enterprises was established in 1976 with motto of providing quality products for Educational Institutions & Research Laboratories. The company has successfully achieved a distinct position owing to its quality products, competent management facilities and total customer satisfaction. Mittal Enterprises has distinction in manufacturing and exporting Lab Instruments, Ultrasonic Instruments like Ultrasonic Interferometer and other Laboratory equipments and Scientific Instruments covered with Trademark, Design Registration and Copy right.
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Objective: Determination of dielectric constant of solids Theory: A dielectric is a material having low electrical conductivity in comparison to that of a metal. It is characterized by its dielectric constant. Dielectric constant is measured as the ratio of the capacitance C of an electrical condenser filled with the dielectric to the capacitance C0 of the evacuated condenser i.e. A simple experimental set up is designed to measure the dielectric constant of solid samples in both range- LOW & HIGH. The experimental set-up consists of: Main Unit having audio oscillator (1 KHz), digital voltmeter (0 – 9.99 V dc), standard capacitance and electronic circuitry. Dielectric Cells: 75 mm Gold plated brass discs (1 set) and 25 mm Gold plated brass discs (1 set). Samples: Low Range: Glass, Bakelite Hi Range: PZT DISC
Objective: Determination of dielectric constant of PZT material with Temperature variation and thus determining Curie Temperature. Theory: Ferro-electricity usually disappears above a certain temperature called the transition (or Curie) temperature. Knowledge of the Curie temperature and the variation of the dielectric constant below and above the Curie temperature are of interest to the physicists and the engineers. In this experiment an LC circuit is used to determine the capacitance of the dielectric cell and hence the dielectric constant. The circuit details are shown below: DC : Dielectric Cell SC : Standard Capacitor L : Induction X : Ferroelectric Sample The dielectric cell DC is placed in PID controlled hot air furnace. The temperature of the furnace can be measured by inserting a thermocouple in a hole (provided on one of the Teflon discs), so that it touches one of the capacitor (metal) plates. The audio oscillator is incorporated inside the instrument. If CSC and CDC represent the capacitances of the standard capacitor and dielectric cell respectively and if VC1 and VC are the voltages across SC and DC then By measuring VSC & VDC and using the value of CSC we can determine the capacitance of the dielectric cell containing the sample. If C0 represents the capacitance of the dielectric cell without the crystal and the plates separated by air gap whose thickness is the same as the thickness of the crystal then C0 is given by where r represents the radius of the crystal and d represents its thickness The dielectric constant of the crystal at any given temp. is given by The Setup facilitates determination of dielectric constant of PZT sample at different temperature. Dielectric Constant increases as temperature increases, and near Curie temperature, it shows a steep increase and reaches a peak at Curie Temperature.
Planck's Constant Kit Objective: Determination of Planck's constant using light emitting diodes (LED's) by observing the 'reverse photo-electric effect'. Theory: If a bias voltage is passed across the LED, which is equal or greater than the difference in the energy of the bands, i.e. the barrier potential, then the bands will 'line up' and a current will flow. When current flows, electrons flow from the conduction band of the N type conductor and are forced up into the conduction band of the P type. Since the P type conductor's valance band is lacking in electrons and we are overpopulating its conduction band with the bias voltage the electrons readily fall into the 'holes' in the valance band of the P type conductor. When they fall, this energy is released in the form of a photon. The energy of the photon emitted can be written as: Where h is Planck’s constant and v is its frequency. The energy of one electron is the charge of an electron (i.e. the current flow of one electron per second in amps) times the voltage. Using this knowledge we then form the equation: where e = 1.6 x 10-19 C (electron charge) We then solve equation (1) for h and replace the E term with the equivalent of E in equation (2), as well as replace with: Where c = 3 x 108 m/sec (speed of light) We then get: or this equation can be rewritten as It is this equation that we will use to determine Planck's constant. The Setup facilitates determination of Planck's Constant (h) by measuring the voltage drop across light-emitting diodes (LEDs) of different colors at a constant current. Current is chosen such that bulk resistance of the LED is neglected. A graph of V vs. λ-1 is plotted and its gradient gives the value of Planck's Constant as per equation (5). Planck’s Constant Kit consists of the following parts: Specially designed variable dc power supply (0 – 5 V) whose output can be varied in steps of 1 mV. Digital dc Micro ammeter (0-999 µA dc), Digital Voltmeter (0 – 9.99V dc), Calibrated LEDs: 4 nos
Ultrasonic Interferometer For (Solids) Non-Destructive Testing of Material is an important part of Engineering Education as it gives information without deformation in the shape and size of the material. One of the NDT techniques, Piezoelectric Technique is widely used for the measurement of composition dependent properties such as ultrasonic velocity, compressibility, elastic constant, Young’s modulus and Bulk modulus. Its suitability for metals, plastics, polymers and crystals etc. make it versatile tool for Engineering Physics, Material Science and Polymer Science. This NDT apparatus is being used in several I.I.T.s/Universities/Engineering Colleges for laboratory experiments and Research work. Theory In this technique the specimen is cemented to a quartz rod of identical cross section and resonant frequency of the composite system (fc) is determined using the apparatus. The resonant frequency of the quartz crystal (fq) is also determined. From the knowledge of fq, fc and the masses of the quartz and the specimen, the resonant frequency of the specimen is evaluated using the relation Using the value of, the length of the specimen and the density of the specimen, the velocity of the ultrasonic waves in the specimen (v) and compressibility can be calculated using relations whereis density of specimen. Young's Modulus of specimen is calculated using relation Instrument: It consists of Piezoelectric Oscillator, power supply, quartz rod, holder, quartz rod with sample, connecting cables and R.F. meter. Accessory: Any general purpose C.R.O. (not supplied with the instrument)
Removed demands expense account in outward tedious do.