摘要:

One of the problems the student encounters when working with partners or in ’’teams’’ in physics laboratories is identifying the role each participant is to play in doing the experiment and writing the report. In this article we outline a very successful approach to solving this problem while, at the same time, teaching technical report writing as outlined in theAIPStyleManual.

ISSN:0002-9505    

DOI:10.1119/1.10239

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

An approximate method of calculating scattering cross sections is presented. Newton’s second law and the conservation of energy are used to relate the scattering angle to the impulse delivered to the projectile by the scatterer. In order to calculate the impulse, it is necessary to know the time dependence of the trajectory. We assume that the projectile travels the two asymptotes to the actual trajectory with constant velocity.

ISSN:0002-9505    

DOI:10.1119/1.10240

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Recent measurements of the velocity of electromagnetic waves involving simultaneous high‐precision determinations of the frequency and wavelength of highly monochromatic radiation sources are reviewed. After an account of the frequency stabilization of lasers using Lamb‐dip and saturated molecular absorption techniques, the recent measurements of visible and infrared frequencies at NBS (Gaithersburg), NBS (Boulder), and NPL (Teddington) are discussed. The resulting experimental values for the velocity of lightinvacuoare summarized, and the remarkable improvement in our present knowledge ofcobtained from these laser measurements is indicated. The article concludes with a discussion of the suggestion that the velocity of light should be made a defined constant and of the effect such a definition would have on future light‐velocity measurements.

ISSN:0002-9505    

DOI:10.1119/1.10241

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

We calculate exactly the equilibrium properties of a large system consisting of two kinds of Bose particles,aandb, that can be transformed into each other by an external field. The enhancement in the specific heat around the threshold (internal excitation) energy of thebparticles is studied as a function of the external field strength, and the mass–action law is derived. Bose–Einstein condensation can occur in our mixture of reacting gases at a transition temperature lower than that of a one‐component ideal gas. Also, the condensate occupancy increases faster thanT3/2as the temperature is lowered.

ISSN:0002-9505    

DOI:10.1119/1.10242

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Californium‐252 in microgram quantities serves as a convenient and efficient laboratory neutron source for activation experiments. The properties of such sources are described. Experimental procedures and results are presented to illustrate the saturation of activity, half‐life determination, simple γ spectra, and hot‐atom chemistry.

ISSN:0002-9505    

DOI:10.1119/1.10243

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Two experimental apparatus which may be used for laboratory or classroom demonstration of the skin effect phenomenon are described. The first apparatus shows the decrease of a magnetic field as it penetrates a thickness of metal. The second demonstrates the decrease with depth of current in a wire.

ISSN:0002-9505    

DOI:10.1119/1.10244

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Thermally stratified water has a refractive index that varies with height. If an object passes through the water, the waters part at its front and rejoin at the rear. The rejoining waters are seldom in perfect register vertically, so the surface of confluence between them is marked by a jump in temperature and therefore in refractive index, and is visible in shadowgraphic projection. Two shadowgraphs in stereo display the surface in three dimensions. If the shape and motion of any surfaces of confluence are known, the motion of the fluid everywhere else can be computed. The observer seems automatically to do this calculation approximately in his head. As a cheap, convenient, mathematically elegant, and psychologically natural way of displaying flow phenomena, the method should have a place in the teaching of hydrodynamics.

ISSN:0002-9505    

DOI:10.1119/1.10245

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

A general physical science course employing mainly original readings and taught primarily by the discussion method is described. A free type of discussion class seeking to stimulate learning is advocated in favor of direct teaching. While most of the effort is spent on basic scientific questions, these are studied for the insights they can provide the general student into the meaning of explanation, understanding, and reality.

ISSN:0002-9505    

DOI:10.1119/1.10246

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Dirac bra and ket notation is developed for three‐dimensional space. A number of transformations, closure relations, and projection operators are discussed in some detail. The formal results are applied to examples pertaining to homogeneous isotropic and anisotropic systems, as well as to sums over photon polarization degrees of freedom. Most of the discussion is tailored for the student before his exposure to operator methods of quantum mechanics.

ISSN:0002-9505    

DOI:10.1119/1.10247

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.10248

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP