AAPT Logo
AJP Logo
 
   
 

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

Dec 1990

Volume 58, Issue 12, pp. 1127-1219

back to top
RSS Feeds

Preserving and cherishing the Earth—Biblical ‘‘Crimes against creation’’

Robert C. Fleck, Jr.

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1127

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.70.+w Philosophy of science

Preserving and cherishing the Earth

Howard J. Van Till

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1127

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.75.+m Science and society

A joint commitment for the destruction of science

Frank Loreti

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1127

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.75.+m Science and society

Computers mean more physics, less math, in classroom

W. P. Lonc

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1128

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.50.ht Instructional computer use
back to top
RSS Feeds

Editorial: Is clear teaching good teaching? A tale of two teachers

Robert H. Romer

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1129

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.40.G- Curricula and evaluation
back to top
RSS Feeds

Bell’s theorem without inequalities

Daniel M. Greenberger, Michael A. Horne, Abner Shimony, and Anton Zeilinger

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1131 | Cited 305 times

Full Text: | Download PDF

Show Abstract
It is demonstrated that the premisses of the Einstein–Podolsky–Rosen paper are inconsistent when applied to quantum systems consisting of at least three particles. The demonstration reveals that the EPR program contradicts quantum mechanics even for the cases of perfect correlations. By perfect correlations is meant arrangements by which the result of the measurement on one particle can be predicted with certainty given the outcomes of measurements on the other particles of the system. This incompatibility with quantum mechanics is stronger than the one previously revealed for two‐particle systems by Bell’s inequality, where no contradiction arises at the level of perfect correlations. Both spin‐correlation and multiparticle interferometry examples are given of suitable three‐ and four‐particle arrangements, both at the gedanken and at the real experiment level.
Show PACS
03.65.Ta Foundations of quantum mechanics; measurement theory

Electron wavelike behavior: A historical and experimental introduction

G. Matteucci

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1143 | Cited 1 time

Full Text: | Download PDF

Show Abstract
Following the Fresnel theory of light and the consequent scientific debate that his formulation generated, two key experiments with electrons, diffraction by means of a circular hole and a circular obstruction, have been realized to show the existence of the Fresnel zones and of the so‐called ‘‘Poisson spot.’’ The basic arguments concerning the quantum mechanical nature of electrons can be introduced by taking advantage of the vivid impression stimulated by the experimental images.
Show PACS
01.65.+g History of science
03.65.Ta Foundations of quantum mechanics; measurement theory

Lindhard’s paradox—Diffusion of magnetic field into a perfect conductor

A. B. Pippard

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1147

Full Text: | Download PDF

Show Abstract
This paper develops the argument, presented briefly by Lindhard in 1953, that a perfectly conducting metallic sample is unable to keep out a steady magnetic field, since even in the absence of collisions the field energy can still be reduced by transfer to the electron assembly. For a plane slab the analysis, which is given in detail, is an extension of the theory of the anomalous skin effect, and the ineffectiveness concept plays the same role in elucidating the physical mechanism. In samples of other shapes, interaction with the field may not be so narrowly confined to a small fraction of effective electrons, but it is suggested that the diffusion of magnetic field nevertheless proceeds at a rate that is usually rather indifferent to shape.
Show PACS
41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems
72.15.Gd Galvanomagnetic and other magnetotransport effects
75.90.+w Other topics in magnetic properties and materials (restricted to new topics in section 75)

Laboratory observation of elastic waves in solids

Thomas D. Rossing and Daniel A. Russell

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1153 | Cited 7 times

Full Text: | Download PDF

Show Abstract
Compressional, torsional, and bending waves in bars and plates can be studied with simple apparatus in the laboratory. Although compressional and torsional waves show little or no dispersion, bending waves propagate at a speed proportional to (f)1/2. Reflections at boundaries lead to standing waves that determine the vibrational mode shapes and mode frequencies. Boundary conditions include free edges, simply supported edges, and clamped edges. Typical mode shapes and mode frequencies for rectangular bars, circular plates, and square plates are described.
Show PACS
62.30.+d Mechanical and elastic waves; vibrations
01.50.Pa Laboratory experiments and apparatus

Measurements of the superfluid transition in helium by means of a vibrating reed

E. N. Martinez, P. Esquinazi, and J. Luzuriaga

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1163

Full Text: | Download PDF

Show Abstract
A relatively simple method is presented that has been used in an undergraduate experimental course for observing the superfluid transition in 4He. The experimental technique consists of submerging a vibrating reed in liquid helium and observing the changes in frequency and damping (energy dissipation) as the temperature is regulated above and below the superfluid transition. The results of the measurements are interpreted by means of a simplification of the acting hydrodynamic forces, and it is seen that most of the relevant physics is well described by the approximations.
Show PACS
01.50.Pa Laboratory experiments and apparatus
67.25.D- Superfluid phase

Conduction current and the magnetic field in a circular capacitor

D. F. Bartlett

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1168 | Cited 1 time

Full Text: | Download PDF

Show Abstract
From the perspective of Ampere’s circuital law, either displacement current or conduction current can be viewed as the source for the magnetic field inside a circular capacitor that is slowly being charged. The Biot–Savart law is more selective. How it can be used with conduction current alone is shown. Also considered is the ‘‘leaky capacitor. Here it is shown that an isolated charged capacitor which discharges slowly in a homogeneous Ohmic dielectric produces no magnetic field anywhere. Alternatively, a field is produced if the conducting material is confined to a limited region. This field is calculated for a circular capacitor when only the material in the gap is conducting.
Show PACS
03.50.De Classical electromagnetism, Maxwell equations
41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems
84.32.Tt Capacitors

Coriolis and magnetic forces: The gyrocompass and magnetic compass as analogs

Geoffrey I. Opat

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1173 | Cited 1 time

Full Text: | Download PDF

Show Abstract
The Coriolis force on a particle (acting within a rotating frame) and the magnetic force on a charge, are both proportional to and act perpendicular to the velocity. As a consequence, the action of the Coriolis force on rotating mass, and the action of the magnetic force on rotating charge are formally identical. Just as the action of a magnetic field is to align the axis of the rotating charge distribution (magnetic dipole) with itself, so the Coriolis force aligns the axis of a rotating mass distribution (angular momentum) with the angular velocity of the rotating frame. This enables us to understand the gyrocompass by analogy with the magnetic compass. A simple way to demonstrate the gyrocompass to a class is also presented.
Show PACS
45.05.+x General theory of classical mechanics of discrete systems
07.10.-h Mechanical instruments and equipment

A hydrogenic atom in d‐dimensions

Keith Andrew and James Supplee

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1177 | Cited 4 times

Full Text: | Download PDF

Show Abstract
The laws of physics in d spatial dimensions are interesting and often lead to insights concerning the laws of physics in three spatial dimensions. A hydrogenic bound system in d‐dimensions is investigated where d is any real positive number, not necessarily an integer, and where a d‐dimensional radial Schrödinger equation is defined by the analytic continuation of the Schrödinger equation used in integer dimensions, with a d‐dimensional potential defined by Gauss’ law. The fundamental constants and physical relationships in d dimensions are arrived at by assuming the electric flux obeys a Gausslike law in d dimensions. This fixes the potential and makes it possible to write down the d‐dimensional Schrödinger equation. This equation is then solved numerically for the ground‐state energy eigenvalues, for several different dimensions, using a fourth‐order Runge–Kutta predictor algorithm. The solutions to this equation are compared to the analogous Bohr model energies in d dimensions and to the results obtained by others at well‐known integer dimensions. There is good qualitative agreement between the two theories in all dimensions. In addition, the wave functions for the Schrödinger equation are numerically determined and normalized in order to locate the most probable orbital radius. These values are compared to the d‐dimensional Bohr radii.
Show PACS
03.65.Ge Solutions of wave equations: bound states

The two‐dimensional hydrogen atom with a logarithmic potential energy function

K. Eveker, D. Grow, B. Jost, C. E. Monfort, III, K. W. Nelson, C. Stroh, and R. C. Witt

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1183

Full Text: | Download PDF

Show Abstract
Recently, a ‘‘shooting’’ method has been used to obtain exact expressions for eigenvalues and eigensolutions of the two‐dimensional hydrogen atom. This paper shows that the shooting method is easy for undergraduate students to understand and implement numerically. The highly accurate approximations for both eigenvalues and eigensolutions are then used to contrast the two‐dimensional and three‐dimensional hydrogen atoms. Finally, previous methods for solving the two‐dimensional hydrogen atom are compared with the shooting method.
Show PACS
03.65.Ge Solutions of wave equations: bound states

Newton’s first two laws of motion are not definitions

James L. Anderson

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1192 | Cited 1 time

Full Text: | Download PDF

Show Abstract
Newton’s first two laws of motion are often taken to be a definition of force. It is argued that they are true laws in that they make statements about the nature of the physical world. In particular, the first law can be viewed as asserting the existence of an ensemble of trajectories in a four‐dimensional space along which force‐free bodies, if they exist, would move. Such an ensemble, together with Newton’s absolute time, constitute the essential ingredients of the underlying geometrical structure of Newtonian space‐time. If this view is accepted, it is a relatively simple matter to describe how special and general relativity differ from Newtonian mechanics.
Show PACS
45.05.+x General theory of classical mechanics of discrete systems

Precise calculation of the electrostatic force between charged spheres including induction effects

Jack A. Soules

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1195 | Cited 6 times

Full Text: | Download PDF

Show Abstract
The method of images is applied iteratively to compute precisely the electrostatic force between charged spheres. The results are compared to the experimental results reported by Coulomb and show that Coulomb overlooked induction effects revealed in his data.
Show PACS
41.20.Cv Electrostatics; Poisson and Laplace equations, boundary-value problems
41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems
back to top
RSS Feeds

Tunneling through Fibonacci barriers

D. Kiang, T. Ochiai, and S. Daté

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1200 | Cited 1 time

Full Text: | Download PDF

Abstract Unavailable
Show PACS
61.43.Fs Glasses
61.43.-j Disordered solids
61.44.Br Quasicrystals
73.40.Gk Tunneling
02.10.De Algebraic structures and number theory

The simple variational wavefunctions for the helium atom and the virial theorem

K. L. Liu and Wai‐Kee Li

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1202 | Cited 1 time

Full Text: | Download PDF

Abstract Unavailable
Show PACS
03.65.Ge Solutions of wave equations: bound states
03.65.Db Functional analytical methods
31.15.-p Calculations and mathematical techniques in atomic and molecular physics

A note on the generalized Hellmann–Feynman theorem

S. Balasubramanian

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1204 | Cited 1 time

Full Text: | Download PDF

Abstract Unavailable
Show PACS
03.65.Fd Algebraic methods

The Doppler effect and conservation laws revisited

Dragan V. Redžić

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1205

Full Text: | Download PDF

Abstract Unavailable
Show PACS
03.30.+p Special relativity

Comments on ‘‘General Compton effect via Lorentz transformation,’’ by D. Wilkins [Am. J. Phys. 56, 1044–1045 (1988)]

Abbas Asgharian

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1208

Full Text: | Download PDF

Abstract Unavailable
Show PACS
03.30.+p Special relativity
13.66.-a Lepton-lepton interactions

Comment on ‘‘Linear least‐squares fits with errors in both coordinates,’’ by B. C. Reed [Am. J. Phys. 57, 642–646 (1989)]

Patrick T. Squire

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1209 | Cited 2 times

Full Text: | Download PDF

Abstract Unavailable
Show PACS
07.05.Hd Data acquisition: hardware and software
07.05.Kf Data analysis: algorithms and implementation; data management
07.05.Rm Data presentation and visualization: algorithms and implementation
02.60.Ed Interpolation; curve fitting
back to top
RSS Feeds

Controlling the temperature of solid samples

Saeid Rahimi, René Woolcott, Jr., and Vern Shuck

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1210 | Cited 1 time

Full Text: | Download PDF

Abstract Unavailable
Show PACS
07.20.-n Thermal instruments and apparatus
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

Comparison of the gyromagnetic ratios of the 1H and 19F nuclei—A student experiment

G. R. Davies

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1212

Full Text: | Download PDF

Show Abstract
A technique to determine gyromagnetic ratios of nuclei is demonstrated that does not require a magnetic field measurement or a probe head change. (AIP)
Show PACS
01.50.Pa Laboratory experiments and apparatus
21.10.Ky Electromagnetic moments
27.10.+h A ≤ 5
27.20.+n 6 ≤ A ≤ 19
back to top
RSS Feeds

The Emperor’s New Mind: Concerning Computers, Minds, and the Laws of Physics

Roger Penrose, Author and N. David Mermin

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1214

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.30.-y Physics literature and publications
01.70.+w Philosophy of science
03.65.Ta Foundations of quantum mechanics; measurement theory
89.20.Ff Computer science and technology

Experimental Physics

R. A. Dunlap, Author and David G. Haase

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1216

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.30.mm Textbooks for graduates and researchers
07.90.+c Other topics in instruments, apparatus, and components common to several branches of physics and astronomy (restricted to new topics in section 07)
29.40.-n Radiation detectors
29.50.+v Computer interfaces

Techniques for Nuclear and Particle Physics Experiments

William R. Leo, Author and David G. Haase

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1216

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.30.mm Textbooks for graduates and researchers
07.90.+c Other topics in instruments, apparatus, and components common to several branches of physics and astronomy (restricted to new topics in section 07)
29.40.-n Radiation detectors
29.50.+v Computer interfaces

Quantum Mechanics: An Introduction

Walter Greiner, Author and Joseph Dreitlein

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1217

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.30.mp Textbooks for undergraduates
03.65.Ta Foundations of quantum mechanics; measurement theory

German National Socialism and the Quest for Nuclear Power: 1939–1949

Mark Walker, Author and Raymond G. Stokes

American Journal of Physics -- December 1990 -- Volume 58, Issue 12, pp. 1218

Full Text: | Download PDF

Abstract Unavailable
Show PACS
01.30.Ee Monographs and collections
01.65.+g History of science
01.75.+m Science and society
28.90.+i Other topics in nuclear engineering and nuclear power studies (restricted to new topics in section 28)
Close

AAPT on:

close