摘要:

This paper gives a more detailed description of the “x-ray-flashbulb” experiment for observing the scattering of light by light in vacuum. It is shown here that at least ten to twenty scattering events can be initiated by two x-ray flashbulbs, properly oriented and synchronized to flash together in an appropriate experimental arrangement.

ISSN:0002-9505    

DOI:10.1119/1.1973484

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

With the current emphasis on computers in science and engineering, it is felt that the undergraduate of such disciplines should be introduced to the applications of the computer as early in his educational program as feasible. With this premise in mind, an IBM 1620 computer has been put to use in an undergraduate light and optics laboratory course, generally taken by sophomores and/or juniors. Several experiments that are performed in the laboratory, together with their respective computer programs, written for the 1620 in FORTAN II language, are presented.

ISSN:0002-9505    

DOI:10.1119/1.1973486

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

Experiments on a multisectioned noncalculus introductory physics course are described. The aims were to provide opportunity for individual instruction for those who wanted it, to increase student-to-student help, and to improve motivation. The idea was to achieve these aims through changes in the pattern of operation or the rules of the game, rather than through improvements in presentation or selection of subject matter. Further boundary conditions were that faculty time was not to be increased and that rigor was not to be lessened. New features tried were: the substitution of open-office sessions for half of the classes; a student self-help room; a weekly printed handout; extra credit paperback reading. Finite progress was made; in particular (in the author's opinion), a larger fraction of the students developed lively interest in the subject than had been the case previously.

ISSN:0002-9505    

DOI:10.1119/1.1973488

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

The derivation of the generalized Boltzmann equation is presented from a more elementary viewpoint than that given by Bogoliubov and others working in the field of kinetic theory of gases. Like the other derivations, the starting point is the Bogoliubov, Born, Green, Kirkwood, and Yvon (B-B-G-K-Y) hierarchy equations. However, no formal attempt is made to obtain corrections to account for three or more body collisions. Furthermore, there is noa prioriassumption made that the lower-order distribution functionsFs(s≥2)are functions of time through the one-particle distribution functionF1.

ISSN:0002-9505    

DOI:10.1119/1.1973490

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

This communication describes a simple demonstration of photoconduction in CdS. The method is a quasi-stationary one. From an analysis of the photocurrent as a function of the light intensity, some of the major features of the photoconductive process can be demonstrated.

ISSN:0002-9505    

DOI:10.1119/1.1973492

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

Although a proper derivation of Ohm's law for a particular material should be based on a quantum mechanical treatment of that material, it is interesting to see how far one can proceed on a purely macroscopic basis. It is shown here that for homogeneous, isotropic materials, one can expect an odd voltage-current relation, and that ordinarily Ohm's law will be obeyed as accurately as one wishes over some range of voltage and current. Only the ideas of causality, symmetry, and analyticity are used. Further, if Ohm's law is followed exactly by a material at constant temperature but the resistance is a function of the temperature, and the departure from Ohm's law is due entirely to Joule heating, then it is shown that the odd voltage-current relation still obtains.

ISSN:0002-9505    

DOI:10.1119/1.1973494

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1973496

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1973498

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1973502

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1973506

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP