摘要:

An appraisal of the current state of the art of undergraduate physics instruction in the United States is followed by a review of some steps that are being taken toward the improvement of courses and curricula. These include conferences on curricula for physics majors, experiments with new introductory courses, the formation of study groups to develop ways of presenting various parts of physics, and the development of teaching aids (such as resource letters, paperback books for supplementary reading, films, apparatus for laboratories and demonstrations, and tests for evaluating curricular changes). The work of individual physicists, physics departments, and professional organizations is covered, along with that of the Commission on College Physics. Three appendices give the history of the Commission since its formation in 1960.

ISSN:0002-9505    

DOI:10.1119/1.1941767

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

The Laplace transform has been applied to solve a class of problems in wave propagation that are converse to the well-known time-dependent Boundary Value Problems (BVP). From a knowledge of time-varying conditions on a suitably restricted set of points interior to a region, it is possible to deduce time-varying boundary conditions. These standard situations in slab, cylindrical, and spherical geometry have been treated for the finite domain. The solution of an Interior Value Problem (IVP) in the semi-infinite domain explicitly demonstrates the formulation of an advanced solution in contrast to the retarded solution for a Boundary Value Problem. Corresponding problems in heat conduction will be discussed in a subsequent article.

ISSN:0002-9505    

DOI:10.1119/1.1941768

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

The general Lorentz transformations are derived on the basis of a set of postulates which are fully consistent with the underlying ideas of Newtonian mechanics, but which of course do not include the independent postulate of absolute simultaneity. Thus, the assumption of the constancy of the vacuum speed of lightcis not introduced as a starting point. Instead, the given development leads to a universal critical velocity, and the two alternatives of its value being infinite or finite, correspond to the Newtonian and the relativistic kinematics, respectively, with the critical velocity identified with the experimental valuecin the latter case.

ISSN:0002-9505    

DOI:10.1119/1.1941769

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

A physics course for students in the humanities is described. The course combines a detailed study of mechanics, particularly kinematics, with reading assignments stressing the interaction of science with art, literature, history, government, and other facets of contemporary society.

ISSN:0002-9505    

DOI:10.1119/1.1941770

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

Kirchoff and Liouville have derived the general initial value solution to Maxwell's equations in vacuum, i.e., the wave equation. Such a calculation is presented here for the case of a cold, collisionless, uniform, electron plasma.

ISSN:0002-9505    

DOI:10.1119/1.1941771

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

A simple derivation is given of the Fermi formula for the contact hyperfine interaction energy between the magnetic moment of a nucleus and that of the surrounding electrons. Considerably fewer mathematical and more physical arguments are used than in previous derivations. It is shown that the contact hyperfine field at the nucleus is necessarily equal to the magnetic induction in the interior of a sphere possessing a uniform electronic magnetization. The simplifications achieved in the present derivation do not seem to result in a loss of rigor, and they do not require the introduction of essentially new assumptions.

ISSN:0002-9505    

DOI:10.1119/1.1941772

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

In pre-relativity times, Thomson, Heaviside, and Sommerfeld, among others, had examined questions arising from the assumption that a particle may move faster than the velocity of lightin vacuo. Such a hypothesis is reexamined in the framework of classical (nonquantum) theory of special relativity.

ISSN:0002-9505    

DOI:10.1119/1.1941773

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

The construction of a student-laboratory, Fabry-Perot interferometer is described, together with its use in three experiments. The first is a basic experiment for making some optical measurements. The second uses the interferometer to measure the index of refraction of a gas, and the third uses it to observe the Zeeman effect.

ISSN:0002-9505    

DOI:10.1119/1.1941774

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

The concepts of cavity potential (electrostatic potential in a cavity in a conductor) and Fermi potential (energy per unit charge for an electron at the Fermi level) are defined and used to discuss the work function, contact potentials, Ohm's law, electrode-solution equilibria, and chemical emf's. With the introduction of the entropy transport per unit charge for electrons in a metal (S*), the Seebeck, Peltier, and Thomson effects are elucidated, and the fact that no emf exists at a thermal junction is made clear. Certain other common confusions are cleared up. It is suggested that use of this conceptual scheme will allow the basic physics of these important processes to be taught effectively in general physics courses.

ISSN:0002-9505    

DOI:10.1119/1.1941775

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP

摘要:

A versatile RC-filtered power supply and a calibrated direct-coupled amplifier are described. The power supply furnishes operating power to various electronic devices developed for two large introductory laboratories. It provides about 250 V dc at its rated output of 70 mA, and 2.5 A at 6.3 V ac. The direct-coupled amplifier has 6 output ranges, from 0.5 to 150 V full scale. Its normal input resistance is 22 MΩ, with stable operation at input resistances of 125 MΩ being practical. Output is displayed on an external 100-μA meter. The method of achieving calibration accuracies of ±2% or better, using ±10% tolerance carbon resistors is described. Both instruments are stable and extremely reliable, requiring only standard commercial components and conventional tools and techniques for construction. The cost for parts is $16.26 and $22.05, respectively. The article contains full information regarding construction.

ISSN:0002-9505    

DOI:10.1119/1.1941776

出版商:American Association of Physics Teachers    

年代:1962

数据来源: AIP