bluuebunny/crossref_metadata_2025 huggingface dataset:
Why is the Schwarzschild Solution Independent of the Spatial Stresses?
Authors: Deser S. , Laurent B. E.
Published: August 2005

The following paradox is raised and resolved: Both the energy density T00 and the spatial stresses Tkl are (independent) sources of the tensor gravitational field in general relativity. Yet the general Schwarzschild exterior solution depends only on one parameter m, related to T00, so that no properties of Tij “propagate” to affect an outside observer.
Biography of the X Unit—The X-Ray Wavelength Scale
Authors: Thomsen John S. , Burr A. F.
Published: August 2005

The need for a separate unit of length for x-ray wavelengths is discussed and compared to the case of electrical units. The introduction and development of the x unit is reviewed. It was effectively defined in terms of calcite crystals and was intended to be very nearly equal to 10−11 cm. The numerical value used to specify it was based on Siegbahn's value of the grating constant of calcite measured relative to rock salt. The latter value had been computed by Moseley from the density of rock salt and from Avogadro's number, which in turn rested on the erroneous Millikan oil-drop value of electronic charge. Ruled grating measurements of x rays eventually revealed the discrepancy. Variations observed among calcite crystals indicated the desirability of basing the definition on a standard wavelength rather than a species of crystal. For these reasons, Bearden, while preparing a new x-ray wavelength table, defined a new Å unit in terms of the W Kα1 wavelength (λw kα1  0.209 010 0 Å). This scale eliminates the major problems associated with the old x unit. The numerical factor was chosen to make the experimental value of the conversion factor to absolute units (angstroms) unity on the basis of the data then available; the estimated probable error was given as 5 ppm.
On the Validity of Converting Sums to Integrals in Quantum Statistical Mechanics
Authors: Stutz Conley
Published: August 2005

A method is presented for converting sums which appear in quantum statistical mechanics to integrals using the Euler summation formula. The range of the parameters over which the conversion ∑ nfn→ ∫ f(t)dt is valid can be determined by requiring that all other terms in the formula be negligible as compared to the integral of the function. The determination of the range of the parameters using the formula is illustrated through two simple examples.
Obliquity Factors of Huygens and Kirchhoff Theories Applied to Experimental Diffraction by Two Long, Coplanar, Parallel Strips
Authors: DeAcetis Louis A. , Lazar Irving
Published: August 2005

Fraunhofer diffraction by two long, thin, parallel conducting strips in a plane is investigated experimentally using microwaves whose wavelength is of the order of the strip width. The radiation is polarized with the electric field vector parallel to the strip axes. The results are compared with scalar theory, employing either the obliquity factor suggested by Stokes or that obtained in a Kirchhoff theory development. It is found for this polarization that, while both scalar theories give fairly good agreement with experimental results, the one employing Kirchhoff's obliquity factor more closely predicts the results obtained in the laboratory.
Matrices and Superballs
Authors: Strobel George L.
Published: August 2005

Collisions are represented by matrices that relate final velocities to initial velocities. A matrix is presented that describes head-on collisions of two simple pendulums with a common support, assuming small displacements between collisions. This matrix is related to the matrices that describe bouncing superballs, supershells, and supercylinders whose translational velocity is restricted to a plane. Eigenvalue problems for superballs are then presented and solved for a variety of physical situations.
On the Equivalence of Certain Green's Function Expressions
Authors: Cooper R. K.
Published: August 2005

By using an especially simple form of the Sommerfeld-Watson transform, the equivalence is established of quite different appearing expressions for the electrostatic potential obtained by expanding the source function in orthogonal functions of two different coordinates.
The Lorentz Theory of Electrons and Einstein's Theory of Relativity
Authors: Goldberg Stanley
Published: August 2005

The development of Lorentz' theory of electrons is reviewed insofar as it relates to the problem of the electrodynamics of moving bodies. It is shown that the principle of relativity did not play an important role in the Lorentz theory, and that though Lorentz eventually realized the distinctions between his own work and that of Einstein, he was unwilling to completely embrace the Einstein formulation and thereby reject the ether.
A Computer-Guided, General-Education Physics Course
Authors: Kromhout Ora M. , Edwards Steve , Schwarz Guenter
Published: August 2005

The development of an autonomous Computer-Assisted-Instruction (CAI) general-education physics course is described. Based on a one-term conventional course which has been given successfully at Florida State University for several years, the CAI course makes use of an IBM 1500 Instructional System to guide the student through a self-paced program of textbook reading assignments and homework problems, audiotaped lectures, PSSC movies, and film strips of demonstration experiments. The computer provides programmed instruction, giving the student a diagnostic quiz after completion of each unit which he must pass before being allowed to proceed to the next unit. Review lessons on an IBM 1440 Computer System are provided as a supplement to both the CAI course and the conventional course. The CAI course was given for credit to 23 students in the fall of 1967 and to 37 students in the spring of 1968 with satisfactory results which gave some evidence that increasing involvement with CAI seems to produce better grades. Although the number of students involved was small, we conclude that it is possible to give an autonomous CAI physics course that is not only successful in presenting the material to the student, but is also interesting and attractive to the average student.
Engine Efficiencies and the Second Law of Thermodynamics
Authors: Tobin Marvin C.
Published: August 2005

The second law of thermodynamics is stated in the form o∫ dS = o∫ dQ/T = 0 for a thermodynamic system undergoing a cyclic, reversible process. It is shown that this makes it possible to construct a T-S diagram. The Clausius and Kelvin-Planck statements, as well as the properties of the Carnot engine and general statements about engine and refrigerator efficiencies, are deduced from the properties of the T-S diagram.
Image Contrast in Holographic Reconstructions
Authors: Russell B. R.
Published: August 2005

A qualitative discussion of the holographic process is given. The consequence of recording only the intensity at a given surface and using an oblique reference wave is shown to be an incomplete reconstruction resulting in images of low contrast.
Working Model of a Foucault Pendulum at Intermediate Latitudes
Authors: Sears Francis W.
Published: August 2005

A working model of a Foucault pendulum at intermediate latitudes is constructed of a steel drill rod with a steel ball attached at one end. The rod makes an angle of 45° with the rotation axis of a horizontal turntable. The vibrating system is the same as that whose behavior led Foucault to construct his first gravity pendulum.
Infinite Square-Well Potential with a Moving Wall
Authors: Doescher S. W. , Rice M. H.
Published: August 2005

The problem of a particle in a one-dimensional infinite square-well potential with one wall moving at constant velocity is treated by means of a complete set of functions which are exact solutions of the time-dependent Schrödinger equation. Comparison is made with a first-order perturbation treatment, and numerical results are presented for a particle initially in the ground state.
The Reflection and Transmission of Electromagnetic Waves by a Moving Dielectric Slab. II. Solution in a Fixed Frame
Authors: Noble William J. , Ross Carl K.
Published: August 2005

In Part II, the results obtained in Part I for perpendicularly polarized electromagnetic waves reflected and transmitted by an infinite, plane-parallel, homogeneous, isotropic, nondissipative slab when at rest are transformed via the Lorentz and field transformations to obtain a similar solution when the slab is in uniform motion with respect to a “fixed” observer. The dependence of the frequencies and direction of propagation of the reflected and transmitted waves on the slab velocity is determined, and an expression for energy conservation is derived to account for momentum transfer between the slab and the electromagnetic radiation.
Lithium-Drifted Germanium Detectors
Authors: French W. R. , LaShure R. L. , Curran J. L.
Published: August 2005

Lithium-drifted germanium detectors may be profitably used in a variety of experiments in undergraduate physics laboratories. We have attempted to assemble from literature and our own experience an introduction to these devices. Included are some basic experiments relating to the properties of the detectors which are interesting in themselves, but also practical in terms of routine-detector and electronic-system evaluation.
Wave Functions in One-Dimensional Doubly Periodic Potentials
Authors: Laverrière R. , Proriol J.
Published: August 2005

We give a method to obtain the energy bands for a “one-dimensional doubly periodic potential”; some numerical results are presented.
Molecular Velocity Determination through Gas Effusion: Intermediate Laboratory Experiment
Authors: Benenson R. E.
Published: August 2005

An experiment is described to determine the average velocity of gas molecules in a container while effusion takes place through a small hole into vacuum. When the mean free path of the molecules becomes large compared to the hole diameter, the measurement of pressure as a function of time permits the average velocity to be extracted. The equipment and procedure are simple, and an agreement to within 10% of the kinetic theory of gas value has been obtained using an inexpensive McLeod gauge. The experiment has been performed using air, helium, and argon; measurements on air and helium were performed both at room and dry ice temperatures. A formula has been derived to take into account the effect of outgassing of the container walls at low pressures. Average velocities may be extracted either by a hand calculation between pairs of data points, or by using a short computer program for least-squares analysis. A derivation is given in an Appendix for the effect on the effusion of the hole being drilled in a wall of thickness small, but not negligible, compared to the hole diameter. During the initial pump-down period, while the container pressure is still comparable to atmospheric, the pressure-versus-time data can be analyzed in terms of hydrodynamic theory and used to deduce a virtual hole area for the streaming molecules. Measurements of pressure-increase with time in a sealed-off system gave poor agreement with the rate of outgassing needed to fit the effusion data.
The Faraday Dark Space of a Glow Discharge
Authors: Hurt W. B.
Published: August 2005

The continuity equations are solved in the Faraday dark space for an idealized geometry. By invoking the superposition principle, the electric field may be divided into two components: one of which is responsible for maintaining charge neutrality, and the second of which is responsible for current flow. By conceptually dividing the electric field in this way, it is possible to visualize easily the transitions in the current-carrying mechanisms in the Faraday dark space as the anode-cathode separation is increased. The criteria for the appearance of a positive column is also clearly illustrated.
Superconductive Tunneling in the Advanced Laboratory
Authors: Merrill J. R. , Christy R. W.
Published: August 2005

This paper reports an experiment for an advanced laboratory. The experiment concerns superconductive tunneling measurements of the variation of the energy gap in lead with temperature. The tunneling occurs between evaporated aluminum and evaporated lead films which are separated by an aluminum oxide insulator. The experiment is performed by dipping the samples into a liquid-helium storage Dewar and uses very little helium. The measurements include the variation of the energy gap in lead between 4.2°K and the transition temperature of the lead film. Student data are used in the figures.
A Laboratory Measurement of Decay Energy in Electron Capture from Inner Bremsstrahlung Spectrum
Authors: Raj K. , Ramaswamy M. K.
Published: August 2005

We describe an experiment for the measurement of decay energy in electron capture suitable for an advanced undergraduate laboratory. The experiment consists of determining the end-point energy of the inner bremsstrahlung spectrum accompanying electron capture. As an example, we have measured the Fe55-55Mn decay energy and obtain a value of 248±20 keV.
Laboratory Astronomy: A Geometric Experiment to Determine the Orbit of Mercury
Authors: Herr Richard B.
Published: August 2005

An astronomy laboratory exercise is discussed in the context of its use by an introductory class of liberal arts undergraduates. Information concerning the orbit of Mercury is obtained with the emphasis on deriving results by methods readily visualized by such students and from observations they understand. The experiment is believed suitable also for high school classes and, by the described additions, can be adapted for introductory classes more conversant with mathematics and science.
Kinematics of an Ultraelastic Rough Ball
Authors: Garwin Richard L.
Published: August 2005

A rough ball which conserves kinetic energy exhibits unexpected behavior after a single bounce and bizarre behavior after three bounces against parallel surfaces. The Wham-O Super-Ball® (registered by Wham-O Corporation, 835 E. El Monte St., San Gabriel, Calif.91776), appears to approximate this behavior and provides an inexpensive and readily available model of kinematics quite different from that of a point mass or smooth ball. The analysis is most strikingly illustrated by the fact that the ball returns to the hand after three collisions with the floor, the underside of a table, and the floor. Some questions are raised concerning the dynamics of the collision.
Geometrical Basis of Lagrange Multipliers and System Constraints in Mechanics
Authors: Gaskill J. R. , Arenstein M.
Published: August 2005

The effects of constraints imposed on mechanical systems may be analyzed when the constraints are recognized as geometrical surfaces. Each component constraint restricts the motion due to the applied active forces; taken together the constraint surfaces intersect, forming a new dimensionally reduced surface and thus a single constraint. The gradient vectors on each of the component constraint surfaces must sum to the gradient on the reduced surface. Lagrange multipliers are then just scalars which adjust the magnitudes and senses of the gradient vectors on each component geometrical surface so that the gradient on their intersection has the proper magnitude and is directed along the resultant reaction force. Since the resultant gradient lies in a subspace with a basis formed by the component gradients, these component gradients must be linearly independent. The existence of a nonsingular Jacobian transformation from the subspace to the constraint surfaces guarantees its existence with the required dimension, and thus, the validity of the constraints is guaranteed.
Phase Equation in Quantum Mechanics
Authors: Ronveaux André
Published: August 2005

The so-called phase equation is established in a general way for one-dimensional, linear second-order differential equations and for 2×2-linear differential systems. Systematic derivations give phase equations for particular quantum mechanical problems. New results are obtained using elementary mathematical tools, and some problems particularly well adapted for the phase method are suggested.
Least-Squares Adjustment of Weighted Data to a General Linear Equation
Authors: Gerhold G. A.
Published: August 2005

The usual least-squares procedure includes the assumption that the independent variables are absolutely error free. This assumption is invalid for most physical problems and can be removed. The resulting set of equations is given in a form suitable for computer solution, and advantages in using the correct method are discussed briefly.
Internal Navigation without Gyros
Authors: Bradner Hugh
Published: August 2005

The horizontal displacement of an object can be determined by multiply integrating the outputs of two ideal accelerometers mounted on a pendulum on the object. The result is independent of the time history of the displacement or tilts. It is also independent of the damping and natural period of the pendulum, provided that the integration extends from before the displacement occurs until after the pendulum comes to rest.
Transference Numbers in Transient Gas Discharges
Authors: Fisher L. H.
Published: August 2005

A previous discussion of the fractions of current associated with the various kinds of charge carriers in steady-state low-current gas discharges has been extended to plane-parallel low-current density transient discharges in uniformly irradiated ionization chambers, Townsend discharges, and electron drift tubes with attachment.
Sir John Leslie and the Laws of Electrical Conduction in Solids
Authors: Olson Richard G.
Published: August 2005

It is contended that Sir John Leslie provided both a theoretical discussion and a limited experimental confirmation of Ohm's Law in a paper written in 1791 and published in 1824, three years prior to Ohm's presentation in Die galvanische Kette mathematische bearbeitet.
Goethe and the Physicists
Authors: Jaki Stanley L.
Published: August 2005

In recent years several noted physicists suggested that renewed attention should be paid to Goethe, the author of the Farbenlehre, as this work may contain the clues for a satisfactory synthesis between the objective and the subjective. The paper gives a summary of their views, and probes into Goethe's motivations and procedures as regards his avid pursuit of the investigation of colors. The history of the reaction of physicists to the Farbenlehre suggests that its author can hardly be considered as a safe guide toward a culture surmounting the division between science and the humanities.
A Study of Temperature Dependent Cooperative Phenomena in Coupled Oscillatory Systems
Authors: Neidhardt W. Jim
Published: August 2005

Thermal correlation functions are studied for N-particle systems with harmonic coupling. A simplified derivation is given for pair correlation functions and the temperature dependence of such functions is examined in the high and low temperature limits. Finally, systems of identically coupled particles with free and fixed ends are considered as a function of varying particle number and it is established that systems of small particle number (5–7) have the same pair correlations as an infinite system.
Use of Grating to Find Interferometer White Light Fringes
Authors: Bell Graydon D. , Tubbs Eldred F.
Published: August 2005

A procedure for using a transmission grating to aid in the adjustment of a Michelson interferometer for white light fringes is described. A theoretical analysis of the fringe formation seen in the grating spectrum is given and some ways in which the phenomenon can be used in a student laboratory are discussed.
Construction of Helium-Neon Lasers Operating at 6328 Å
Authors: Malacara D. , Berriel L. R. , Rizo I.
Published: August 2005

The general procedures for designing He-Ne lasers operating at 6328 Å in TEM00 are reviewed. The main parts design considered are the discharge tube, mirrors, windows, and power supply. Some helpful graphs and empirical formulas relating the different parameters are given.
An Undergraduate Experiment Demonstrating Flux Quantization and Superconductivity
Authors: Collings Peter J. , Gordon Joel E.
Published: August 2005

A simple current-sensitive detector which can be used at liquid-helium temperatures is described. It employs Josephson tunnelling and can be easily built in an undergraduate laboratory. The detector itself can be used to observe flux quantization and quantum mechanical interference, or if used in a suitable bridge circuit, to investigate superconducting transitions.
Cluster Configurations in Nuclei
Authors: Meyer Eugene
Published: August 2005

The cluster model of the nucleus is formulated and qualitatively applied to nuclear spectroscopy and nuclear fission. The correlation of states predicted by the cluster model to experimentally known states is presented for twenty nuclei whose structures are built on the clusters Ca40, Ca48, Ni56, and Zr90 plus an alpha, proton, deuteron, triton, or He3.
Archimedes and the Canonical Distribution
Authors: Baierlein Ralph
Published: August 2005

While reading Perrin's classic analysis of the distribution in height of microscopic particles suspended in a liquid, the writer was surprised to find that Perrin applied a correction for a buoyancy effect. How does Archimedes get into statistical mechanics? A simple yet exact calculation with the canonical probability distribution for the case of a microscopic particle in a dilute gas does yield a buoyancy effect. The derivation has intrinsic interest and may be a welcome addition to the traditional applications in an introductory course in statistical mechanics.
Perspective on Physics
Authors: Heims Steve P.
Published: August 2005

A conflict exists between traditional undergraduate physics teaching and the goals of liberal education. A report is given on an undergraduate seminar entitled “Perspective on Science.” The seminar was an attempt to honor the goals of liberal education, and at the same time to teach some physics.
A Magnetic Field Diffusion Problem
Authors: Klauder L. T.
Published: August 2005

This paper presents a solution to the problem of determining the lift and drag on a long, straight, current-carrying wire moving side-ways over a conducting semi-infinite slab.
Multipole Precession
Authors: Moroi David S. , Berge Phillip O.
Published: August 2005

The motion of a nucleus with an intrinsic multiple moment, in particular an intrinsic hexadecapole (16 poles) moment in external electrostatic multiple (triple) field gradients, is studied from a classical point of view. It is shown that in the classical approximation the angular-momentum vector of a nucleus with an intrinsic hexadecapole moment may precess about the direction of greatest triple field gradient. The formulation of the theory can be generalized to the higher-order multipole cases. For the hexadecapole case, the classical precession frequencies are found to be related to the quantum mechanical dipole transition frequencies.
Radiation from an Accelerated Charge and the Principle of Equivalence
Authors: Kovetz A. , Tauber G. E.
Published: August 2005

The connection between an accelerated charge and one at rest in a (weak) gravitational field is discussed in accordance with the principle of equivalence. For that purpose, the fields produced by a freely falling charge and a supported one (i.e., at rest in a gravitational field) are transformed to the rest-frame of the observer, who may be similarly supported or freely falling. A nonvanishing energy flux is found only if the charge is freely falling and the observer supported, or vice versa. This agrees with previously established results.
Least Action via Computer
Authors: Bork Alfred , Zellweger Andres
Published: August 2005

An experimental computer program for a computer with a cathode-ray tube output device was designed to assist beginning students of physics in learning about Hamilton's principle.
A Thermodynamic Consideration of Mechanical Equilibrium in the Presence of Thermally Insulating Barriers
Authors: Curzon A. E.
Published: August 2005

The principle of increase of entropy is used to obtain the condition for mechanical equilibrium in an isolated system divided into two parts by a frictionless, weightless piston which is made of a perfectly thermally insulating material. The result emphasizes that the principle can be used to obtain the condition for mechanical equilibrium without the assumption, frequently made in the textbooks, that the mechanical equilibrium is accompanied by thermal equilibrium.
The Development of Lead Salt Detectors
Authors: Lovell D. J.
Published: August 2005

In 1930, a meeting to discuss photoelectric cells indicated that photoconductive cells were of marginal value. In 1954, interest in photoconductivity was sufficient to warrant a meeting to discuss that topic exclusively. The impetus for this change came largely from the military in its desire to develop a sensitive, reliable infrared detector. The varied investigations involve both German and U. S. A. wartime efforts and subsequent efforts in such diverse laboratories as university, military, and commercial. It is doubtless this diversification that has enabled so many successes to be achieved.
A Time-of-Flight Neutron Experiment for the Undergraduate Laboratory
Authors: Robinson W. K. , Nagi J. L. , Duggan J. L.
Published: August 2005

A neutron time-of-flight experiment is described for use with neutrons from small accelerators. The neutrons were produced for this experiment by the T(d, n)4He reaction. This reaction is the one most commonly used for the production of 14.8 MeV neutrons. The method employed for the measurement is known as associated particle time of flight. For the reaction, neutrons that emerge in the forward direction are accompanied by associated alpha particles that are emitted with an angular separation of approximately 180° with respect to these neutrons. The alpha particles were used to start a time-to-pulse-height converter (TPHC), and the neutrons stopped this timing cycle. The output from the TPHC was a single isolated neutron group whose magnitude was proportional to the difference between the start and stop pulses. In the experiment, the velocity of the neutron is determined, and the total neutron cross section is measured for aluminum, copper, iron, and lead. All measured quantities give results that are in very good agreement with the accepted values. From the total cross-section measurements, a value of the nuclear radius was determined to be 1.3×10−13 A1/3 cm.
Differential Form of the Elastic Collision Operator
Authors: Kelly D. C.
Published: August 2005

The elastic collision integral in the Boltzmann equation can be converted into differential form when it describes the interactions between “light” and “heavy” particles. An elementary and straightforward demonstration of this conversion is effected by expanding the distribution function in powers of the collisional energy transfer.
Precision through Error Generation
Authors: Fajans Jack
Published: August 2005

When the measurement values are discrete, relative to the intrinsic noise level of an experiment, it may be possible to increase accuracy by error generation. Several illustrations are given, and the use of normal law error generation is discussed in detail.
Entropy Differences between Ideal and Nonideal Systems
Authors: Leff Harvey S.
Published: August 2005

The canonical entropy SK for an ideal (noninteracting) system is compared with the canonical entropy SH for a similar nonideal system at the same temperature. Using the Gibbs-Bogoliubov inequality, upper and lower bounds are derived for (SH−SK). For classical fluids and for quantum or classical spin systems, the upper bound is found to be identically zero, yielding SH⩽SK. The classical fluid result agrees with a recent finding of Baierlein and generalizes it to a class of momentum-dependent potentials. The spin system result further extends the scope of Baierlein's inequality. For quantum fluids, a discussion of the bounds is given, but no conclusive results are obtained.
The Free Fall of Atoms
Authors: Johnson Neil B. , Zorn Jens C.
Published: August 2005

The gravitational deflection of beams of potassium atoms having well-defined speeds ranging from 186 m/sec to 551 m/sec has been observed over a horizontal flight path of 2.1 m. The experimental results are consistent with the assumption that individual atoms experience the usual gravitational force. If the experiment is regarded as one to determine g, the result of a least-squares fit of the data to the theoretical expectation yields g = 960±22 cm/sec2.
Cyclotron Echo Phenomena
Authors: Gould Roy W.
Published: August 2005

The physical mechanisms by which echoes are produced in a system of many charged particles gyrating in a static magnetic field is outlined. It is then shown how these ideas carry over to large systems of (almost) harmonic oscillators and are therefore applicable to many other physical systems.
Interaction Energy of Two Axially Symmetric Electrodynamic Systems
Authors: Baggerly Leo L. , Pan Peter N. Y.
Published: August 2005

The electrostatic or magnetostatic interaction energy of two axially symmetry electrodynamic systems, whose axes intersect at an angle α, can be written in terms of a harmonic expansion of Legendre polynomials in α in the form W(1, 2; α) = ΣnUnPn(cosα), where W(1, 2; α) is the interaction energy at the angle α, and Un is the nth partial energy when the symmetry axes coincide. It is shown that if the two distributions (charge or current) do not overlap at any α, then the associated partial energies can be written as the product of two independent multipole moments, an “interior moment” and an “exterior moment.”
Examples of Momentum Distributions in the Electromagnetic Field and in Matter
Authors: Furry W. H.
Published: August 2005

Momentum conservation and the validity of the center-of-mass law are examined for systems made up of electrostatic charges and magnets, in terms of the requirements of special relativity theory. The approach used is that of a quasimicroscopic electromagnetic theory, in which the interaction of the field with material bodies is described by using models for these bodies which involve charge and current densities. It is shown that if small “electromagnetic mass” terms are neglected, both conservation of momentum and the center-of-mass law hold in all cases. In some cases a “hidden momentum” contained in stationary matter plays an important role, as pointed out recently by Shockley and James [W. Shockley and R. P. James, Phys. Rev. Lett. 18, 876 (1967).] In such cases the center-of-mass law can fail in nonrelativistic theory. This is illustrated by the discussion of a special model. Another case in which a “hidden momentum” required by relativity theory is important is the explanation of the null result of the Trouton-Noble experiment. This is discussed in Sec. V.
A Demonstration of the Spring-Mass Correction
Authors: Sears Francis W.
Published: August 2005

The frequency of oscillation of a body of mass m, suspended from a coil spring of mass M and force constant K, is the same as that of a body of mass m* = m+pM, suspended from a mass-less spring of the same force constant. It is shown that the factor p varies from 13, when m≫M, to π2/4 = 0.41 when m≪M. The wave apparatus consisting of a flat steel strip having equally spaced cross-arms is an equivalent system, and the factor corresponding to the mass ratio m/M can be varied over a considerable range by replacing the lowest cross-arm with a rod to which counterweights can be attached.
A Demonstration of Additive Color Mixing Rules under the Influence of Color Contrast
Authors: Holtsmark Torger
Published: August 2005

A simple slide-projector technique, which demonstrates the process of additive color mixing within areas of relatively low luminance as compared with that of the surrounding area, is described. Under such conditions full-hue circle representations can be obtained by means of two colored, and one uncolored beams of light. Some examples of appropriate pairs of color filters are given.
Pressure of an Ideal Gas on a Moving Piston
Authors: Bauman Robert P. , Cockerham Howard L.
Published: August 2005

The pressure exerted by an ideal gas on the face of a moving piston is calculated for constant piston speeds that are small compared to the average speed of the gas molecules, and is found to be proportional to the expression, 1 − (8/π)α + (8/π)α2, where α is the ratio of piston speed to the average molecular speed, or, better, is the ratio of the piston speed, corrected for the motion of the gas in the direction of piston motion, to the average molecular speed. The drift speed of the gas is investigated and found to be proportional to the displacement of the piston and the difference between piston speed and molecular speed. Work done in isothermal and adiabatic processes is calculated. Possible experimental verification is considered.
Thermistor Explorations in a Kundt Tube
Authors: Hastings R. B.
Published: August 2005

The temperature distribution found in standing waves in air in a Kundt tube is investigated by making use of the change in resistance of a thermistor moved the length of the tube. Two procedures are used. In one, values of thermistor currents are read along the tube and plotted against distances. In the other, actual thermistor resistances are measured and similarly plotted. Periodic variation of both current and resistance is evident. Using data obtained from the resistance variation curves, the actual temperature excursion is estimated. From the locations of the nodes and antinodes on current-distance graphs, the velocity of sound is calculated.
Spectrum of Plane Electromagnetic, Magnetostatic, and Spin Waves in a Ferrite Medium
Authors: Seshadri S. R.
Published: August 2005

The dispersion equation for a plane wave propagating in an arbitrary direction with respect to the external magnetic field in an unbounded ferrite medium is recast as a quartic equation in the square of the wave number for the case in which neither the effective exchange magnetic field nor the electric field is neglected. This quartic equation is solved by a perturbation procedure to obtain, in particular, an expression for the wave number in the very close neighborhood of the ferromagnetic resonance frequency, where there is a rapid variation in the dispersion.
Transition Probability of a Linearly Forced Harmonic Oscillator System
Authors: Ninan M. M. , Stipcevic Z.
Published: August 2005

The transition probability of a linearly forced harmonic oscillator system is derived by expanding the evolution operator using an expansion theorem valid for operators obeying the commutation law, (A, B) = 1.
An Instructive Model for the Quantization of Magnetic Monopoles
Authors: Efinger Helmut J.
Published: August 2005

The properties of magnetic monopoles which are placed into an electric field are studied. The model is treated nonrelativistically following the pattern of Landau's diamagnetism. However, the roles of electricity and magnetism are interchanged. We obtain Dirac's value for the monopole strength and find that the total charge which serves as a source for the electric field is to be quantized in accordance with Dirac's prediction.
Some Relativistic Effects in Systems with a Variable Rest Mass
Authors: Pomeranz Kalman B.
Published: August 2005

The dynamics of relativistic systems with a variable mass can be studied by employing the conservation of momentum and the conservation of energy principles of special relativity. The conservation of rest mass does not apply in relativistic mechanics. The correct relativistic equations predict a thrust on a system of varying rest mass which differs in magnitude and direction from the predictions of classical mechanics.
Single Antenna X-Band Doppler Shift Apparatus
Authors: Simpson R. E.
Published: August 2005

A simple one antenna X-band transmitter-receiver for demonstrating the Doppler shift from a moving metal reflector is described. A 132-scale slot car and track provide a convenient constant-speed target whose speed is measured by the Doppler shift. The usable range is over 20 ft.
Dispersion of an Electromagnetic Pulse
Authors: Aksornkitti S. , Hsuan H. C. S. , Lonngren K. E.
Published: August 2005

We describe a relatively simple experiment which demonstrates the concept of dispersion of electromagnetic pulses. The experiment uses standard microwave equipment and clearly shows the spreading of a pulse associated with dispersion.
Second-Order Constitutive Equations for Monatomic Fluids
Authors: McCoy Benjamin J.
Published: August 2005

Second-order transport relations are developed and compared for the Boltzmann, Fokker-Planck, and Krook equations for monatomic molecules. The irreducible expressions for the heat flux and pressure tensor take on identical forms with transport coefficients differing only by factors of unit order of magnitude.
The Physics Workshop at Northeastern University in Boston
Authors: Sharon Y. Y. , McGuire J. H. , Miller M. G. , Morelli L. , Russo M.
Published: August 2005

This paper describes a large-scale, voluntary, and informal project in which physics graduate students at Northeastern University help undergraduates who are taking physics courses. This approach has been of particular benefit to students in the large freshman and sophomore lecture classes. Its appeal is reflected by the high level of participation of both undergraduate and graduate students. On the basis of our experiences at Northeastern University, we also present specific suggestions that could help other departments who may wish to initiate similar programs.
Generalized Compton Equation
Authors: Veigele Wm. J. , Tracy P. T. , Henry E. M.
Published: August 2005

The classic Compton equation was derived for an initially free stationary electron. Expermental results on scattering of x rays from atomic electrons are in disagreement with predictions from the Compton equation, showing a line broadening and a defect of the center of this broadened line toward a wavelength shorter than that predicted by the Compton equation. These effects have been explained separately on Doppler effect and impulse models. In this paper a relativistically covariant formalism including electron binding, described by a heavy electron, is used to derive the general Compton equation containing the line broadening and defect terms. The defect term contains explicit dependence on the scattering angle.
Expansion of Available Phase Space and Approach to Equilibrium
Authors: Sciamanda Robert J.
Published: August 2005

It is shown that those molecular collisions which tend toward equalization of molecular energies also tend to maximize the phase space available to a closed system. This helps to motivate the hypothesis that a functional relationship exists between the thermodynamic entropy and the available phase space for a closed system. The calculation, simple enough for an introductory course, is also illuminating in itself as an insight into the statistical nature of the second law of thermodynamics.
The Nature of Time
Authors: Coe Lee
Published: August 2005

Though used with precision, time is often called a mystery. The paradox is resolved by a theoretical conclusion: time is a general property of matter, described by the law that all isolated material changes occur (or would occur) in invariant ratios to each other. The law of time is a corollary of the first law of thermodynamics.
Information on Some Interesting Satellites
Authors: Merrill John R.
Published: August 2005

This paper deals with sixteen satellites which are of interest to elementary physics courses. Various parameters of the satellites' orbital motions are computed, and accurate plots of some of the orbits are included. The satellites are chosen to give an idea of the various types of orbits which have been achieved by artificial satellites. The computer programs used are available in the language BASIC. The best sources of information on the orbits of the various satellites were the journal Astronautica Acta and Allen's book, Astrophysical Quantities.
Some Comments on a Relativistic Frequency-Shift Experiment of Champeney and Moon
Authors: Sama Nicholas
Published: August 2005

An experiment of Champeney and Moon for Mössbauer emission and absorption on a rotating device is discussed. They obtained a zero frequency shift for emitter and absorber at opposite ends of a rotor, which they concluded to be in accord with the requirements of special and general relativity. However, it is shown here that their experiment requires a null result if the Doppler shift be any function whatever of the speed of the absorber relative to the emitter, and of the angle between the absorber's velocity and the direction of the incident light. Consequently, the conclusion of Champeney and Moon is not really meaningful. Additionally, it is pointed out that if the frequency shift between relatively moving frames is in fact acceleration-dependent, then the experiment indicates that at the very most, the acceleration magnitude only can be relevant.
Diffraction Plates for Classroom Demonstrations
Authors: Hoover Richard B.
Published: August 2005

The diffraction plate, which consists of an array of many identical apertures or obstacles, produces large Fraunhofer diffraction patterns of sufficiently high intensity such that they may be seen easily with the unaided eye when used with conventional sources. If a small, bright source is observed through a diffraction plate held close to the eye, the Fraunhofer pattern of the apertures appears around the image of the source. If the apertures are randomly distributed over the plate, the pattern produced is characteristic of any one of the apertures in the plate. The pattern produced by a regular array has characteristics of both the individual aperture and of the arrangement. The beautifully colored patterns produced by a white light source are easily seen and photographed. This article describes the computer generation of random and regular arrays of apertures and their applications for classroom demonstrations of the Fraunhofer patterns produced by simple and complex apertures, Babinet's principle, resolution according to the Rayleigh criterion, and many other important aspects of diffraction.
Methodology of Thermodynamics
Authors: Mohan Gyan
Published: August 2005

A systematization of the mathematical formulae in thermodynamics is presented.
Phase Transition of a Molecular Zipper
Authors: Kittel C.
Published: August 2005

Two systems of biomolecules in solution are known to be represented by simple models which can be solved to give phase transitions in one dimension. The systems are double-stranded DNA and the helical polypeptides. We treat the very simple problem of the single-ended zipper. There is an interesting simialrity with the work of Nagle on the one-dimensional analog of the Slater model of KDP.
A Perturbation-Operator Approach to Generalized Zeeman Effects
Authors: Arthurs A. M. , Robinson P. D.
Published: August 2005

The advantages of Primas's operator approach to perturbation theory are discussed and illustrated by a type of Zeeman-effect problem. The condition for convergence of the perturbation series is obtained.
A New Electronics Course for Physics Students
Authors: Tan B. T. G.
Published: August 2005

A new electronics course for physics students is described which emphasizes these fields in electronics closely related to physics. Physics students, with their background in solid state physics, are taught semiconductor device physics in greater detail than in most electronic engineering courses. In addition, the course attempts to present a broad view of electronics and its applications to the physics student.
The Meter Stick in the Match Box
Authors: Lang Donald W.
Published: August 2005

An implication of the Lorentz contraction is explored. Texts of special relativity show that a meter stick in an appropriate inertial frame is sufficiently contracted to be entirely contained in a match box. It is shown that with an appropriately transparent match box and sufficient technology, an observer at rest with respect to the match box could obtain a photograph recording the meter stick as entirely contained in the match box. A photograph taken at this spot at the same time by an observer in the inertial frame of the meter stick (or any other) also shows the meter stick overlapped at both ends of the match box. The analysis is valid for all distances between match box and observer.
A Derivation of the Macroscopic Maxwell Equations
Authors: Russakoff G.
Published: August 2005

We derive the macroscopic Maxwell equations from the microscopic equations of electrodynamics. The method is based on a modified version of spatial averaging and unifies several past approaches. For simplicity, the derivation presented here is restricted to classical systems, although it may easily be extended to incorporate quantum mechanical systems.
A Simplified Muon Lifetime Experiment for the Instructional Laboratory
Authors: Hall R. E. , Lind D. A. , Ristinen R. A.
Published: August 2005

An experiment has been developed for the measurement of the half-life of cosmic ray muons by using a single scintillator detector. The associated electronics are much simplified over conventional cosmic ray muon lifetime measuring systems. It is this simplification that makes the experiment well suited for the instructional laboratory.
Visual Appearance of a Moving Vertical Line
Authors: Bhandari Ramesh
Published: August 2005

A vertical line moving with velocity v, when seen, assumes the shape of a hyperbola or parabola accordingly as v < c or v = c. At v > c, which actually is not possible, the line takes the form of an ellipse, or parts of an ellipse, or even becomes imaginary, depending upon the length of the line, the magnitude of the velocity, and the distance of the viewer from the line. If, however, a line moving with v < c recedes from the viewer, it seems less curved until at infinity it straightens up to look vertical again.
Eigenvalues of Two- and Three-Dimensional Systems by Matrix Methods
Authors: Nicola Michel
Published: August 2005

A new method for finding the eigenvalues of two- and three-dimensional systems using matrices is given. The method is based on the principle that a physical variable takes on all the classically permissible values except those ruled out by the uncertainty principle and by the noncommutativity of some of the dynamical variables composing the system. Thus, the uncertainty principle is shown to yield positive results in spite of its negative character.
Newton's Experimentum Crucis Reconsidered
Authors: Holtsmark Torger
Published: August 2005

Certain terminological inconsistencies in the teaching of optical theory at the elementary level are traced back to Newton's Opticks and shown to derive from an uncritical application of the terminology of the old, established Euclidean geometrical optics to experiments which are primarily concerned with the establishment of a physical theory of light. The “ray” of Euclidean geometrical optics should be considered as a geometrical operator, the working rules of which are laid down in a set of axioms. If the Euclidean ray concept is adapted to those dispersion experiments put forward by Newton in favor of his hypotheses, some general class properties of dispersion phenomena are revealed. From the insight in those class properties, certain counter experiments can be easily recognized which demonstrate that it makes no sense to connect a certain color of the ray with its degree of refrangibility. There is a brief discussion of the significance of such experiments for insight into the part played by pure observation in scientific theory making.
Particle Identification and Subsidiary Conditions from Correlation Functions
Authors: Shankland Donn G.
Published: August 2005

A tensor field of any rank can be separated into its fundamental particles by considering the possible forms of its correlation function in momentum space. The constraint equations necessary to project particles of one type can be obtained from the eigenvectors of the correlation matrix.
An Isotropic Approach to Divergence
Authors: Noerdlinger Peter D.
Published: August 2005

The form of the divergence operator in rectangular coordinates is derived by use of an infinitesimal spherical volume instead of the usual cubical one. The derivation shows clearly that the expression does not depend on the orientation of axes.