摘要:

Prepared at the request of the AAPT Committee on Resource Letters; supported by a grant from the National Science Foundation.This is one of a series of Resource Letters on different topics, intended to guide college physicists to some of the literature and other teaching aids that may help them improve course contents in specified fields of physics. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one letter in some of the main subjects of interest. Comments and suggestions concerning the content and arrangement of letters as well as suggestions for future topics will be welcomed. Such communications should be sent to Professor Arnold Arons, Chairman, Resource Letter Committee, Department of Physics, Amherst College, Amherst, Massachusetts.Notation: An asterisk (*) indicates items particularly recommended for introductory study.Additional copies: Available from American Institute of Physics, 335 East 45 Street, New York, New York 10017. When ordering, request Resource Letter SL-1 and enclose a stamped return envelope.

ISSN:0002-9505    

DOI:10.1119/1.1971350

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

Direct-current power supplies with Zener-diode-output voltage regulation are considered in relation to their protection against short-circuiting of their output terminals. It is shown that increasing the input voltage and the series resistance for a given output voltage reduces the ratio of the short-circuit current to the normal load current, allowing the design of power supplies which will sustain prolonged shorting of their output terminals. Criteria for the optimum circuit values for protection are considered. Universal curves of the powers and currents in each part of the circuit are given as functions of the ratio of input to output voltage. The results are generally applicable to Zener diode and glow-discharge-regulator power supplies. The treatment is presented in some detail to emphasize the value of mathematical analysis of apparently simple problems. Brief results are given of measurements on a power supply employing the principles outlined.

ISSN:0002-9505    

DOI:10.1119/1.1971354

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

If an electrostatic field and a magnetostatic field are assumed to be physically of the same species and added together vectorially, after being expressed in common units, the interaction energy between fields is shown to vanish. Noninteraction of the fields, that is, the failure of static charges to have macroscopic influence on stationary magnets, is therefore not a sufficient condition to establish that they are of different species, but may be a result of mathematical form.

ISSN:0002-9505    

DOI:10.1119/1.1971356

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

The relationship between radiation pressure and radiant energy density is examined from the standpoint of photon energy and photon momentum, utilizing geometric optics.

ISSN:0002-9505    

DOI:10.1119/1.1971359

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

The mathematical consequences of assuming heat conduction (or diffusion of particles) in the same sense as the temperature (or concentration) gradient rather than in the opposite sense leads to time reversal in the partial differential equation and the possibility of computing a prior state of temperature from one known in the present. In spite of the similarity in mathematical form for the partial differential equation and solutions, a fundamental physical and mathematical distinction exists in this converse problem with respect to the initial condition permitted for the problem. All temperature distributions assumed as initial conditions fall into three classes with respect to the criterion of how far back in time the time reversal calculation can be carried ideally, but not necessarily in practice. In time reversal, the well-known Green's or Influence Functions become Deinfluence or Concentration or Accumulation Functions as suggested designations with quite different mathematical properties.

ISSN:0002-9505    

DOI:10.1119/1.1971363

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

A simple model is proposed that is useful for understanding the role played by the Coulomb interaction in determining the total orbital angular momentum of an atomic ground state. An example is given and some possible shortcomings of the model are discussed.

ISSN:0002-9505    

DOI:10.1119/1.1971366

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

A different approach to the first-year physics laboratory course, consisting of open laboratory sessions and practical examinations, is described. The responsiblity for the student's development is left much more in his own hands than is customary. The underlying philosophy of the course and its organization is discussed.

ISSN:0002-9505    

DOI:10.1119/1.1971370

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

A consideration of the eigenvalue problem for the quantum-mechanical three-dimensional isotropic harmonic oscillator leads to a derivation of a conserved symmetric tensor operator, in addition to the angular momentum vector operator. Upon examining the classical limit, it is found that the symmetric tensor completely specifies the orientation of the elliptical orbit, in a way analogous to the Runge-Lenz vector for the Kepler problem. The tensor operator and the angular momentum vector operator are then related to the infinitesimal operators for theSU3group.

ISSN:0002-9505    

DOI:10.1119/1.1971373

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

Extensive graphical representations are shown for the magnetic Bravais lattices and for symmetry and antisymmetry operations in the magnetic (or two-color) space groups. With aids of these figures and newly introduced graphical symbols, symmetry characteristics of the magnetic space groups are discussed and some pertinent examples of the magnetic spin structure are cited.

ISSN:0002-9505    

DOI:10.1119/1.1971375

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

Three simple problems concerning random events are proposed and discussed. In each problem some unexpected feature emerges, and an attempt is made to clarify the results in the light of actual practice.

ISSN:0002-9505    

DOI:10.1119/1.1971379

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP