摘要:

Most fundamental questions about gravitation cannot be answered with puny experiments performed in the laboratory. Fortunately, nature provides ready-made experiments on gravitation, and these are performed on a grand scale. Examples are given, and their significance for general relativity is discussed.

ISSN:0002-9505    

DOI:10.1119/1.1974190

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

The problem of relating the statistical mechanics of a weakly interacting system to its macroscopic thermodynamic description is confronted. Following a brief discussion of previous solutions, a treatment exhibiting some novel features is presented—first for a pure system, then with generalization to mixed systems in which combination and dissociation may or may not occur. In each case the second law, along with a small number of explicitly stated additional assumptions, is employed in the derivation of formulas for absolute temperature and entropy in terms of quantities indigenous to the statistical mechanics of the system.

ISSN:0002-9505    

DOI:10.1119/1.1974191

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

An experiment is described which utilizes the Hanle technique for measurement of atomic excited-state lifetimes, with particular application to the3P1state of mercury. The components for the experiment are comparatively inexpensive or readily constructed, and the technique is one of the few which directly illustrate features of the interaction between radiation and free atoms. A simple classical description of the effect is given, followed by a more detailed quantum description, as well as constructional details of an experimental arrangement suitable for an advanced undergraduate or graduate laboratory.

ISSN:0002-9505    

DOI:10.1119/1.1974192

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

A complete, simplified system has been designed and constructed for two types of spark chamber demonstrations: (1) A multiplate chamber for observation of penetrating cosmic rays; and (2) a “curtain-discharge” chamber for observation of β rays from a radioactive source, with curved trajectories in a magnetic field. Attention has been given to minimizing the cost of the components and the difficulties of fabrication and assembly.

ISSN:0002-9505    

DOI:10.1119/1.1974193

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

An experiment for the Rice University Senior Physics Laboratory has been developed around the19F(p, α)16Oreaction. The experiment serves to introduce the student to nuclear spectroscopy in an environment almost identical with the research environment. The experiment makes use of a 5.5-MeV Van de Graaff accelerator and an on-line computer analyzer. The students are given much freedom to choose the measurements to be made, and are expected to devise methods for processing the data accumulated.

ISSN:0002-9505    

DOI:10.1119/1.1974194

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

A recently proposed approach to the formulation of gravitational theory, in which alla priorimention of curvlinear coordinate systems and space-time can be avoided, is illustrated by applying the method to the particular case of the Dirac field. The basic procedure used is that of starting with an invariance property of the special-relativistic free Lagrangian under some class of transformations, identifying the associated conserved “current,” and then finding a field which interacts with this conserved current by requiring that the Lagrangian be altered so it remains invariant even when the original transformations become coordinate-dependent in an appropriate fashion. For purposes of illustration, the technique is first used to derive the electromagnetic interaction of the Dirac field, and then the gravitational interaction of this field is worked out. A comparison of the resulting theory with general relativity is given. The emphasis throughout the paper is on concepts rather than on a detailed mathematical development.

ISSN:0002-9505    

DOI:10.1119/1.1974195

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

A set of sign conventions to be used in the derivation and application of mirror and lens formulas in geometrical optics is proposed. Some examples are presented to show that the formulas derived with the proposed conventions have greater uniformity and that these conventions correspond to the physical process (convergence or divergence) taking place at a spherical reflecting or refracting surface.

ISSN:0002-9505    

DOI:10.1119/1.1974196

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

Spectral representations for two-point functions of point quantum-mechanical systems are derived, under very general assumptions. Sum rules are then obtained, both for systems with velocity independent and dependent interactions. The implications of these sum rules are illuminated on particularized simple systems. Special attention is paid to systems where a zero-frequency (translational) mode exists. The difference between velocity-dependent and -independent interactions is shown to be very crucial in this respect. The same analysis provides an instructive example of inadvertent misuse of the spectral representations. Finally, the possibility of Goldstone behavior, with all its consequences and implications, is demonstrated for systems with finite many degrees of freedom.

ISSN:0002-9505    

DOI:10.1119/1.1974197

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

A formalism is presented in which both the degenerate and nondegenerate cases can be treated in the same fashion. Nonlinear integral equations are written for the perturbed wavefunctions, which lead to the usual formulas when solved by iteration. The method provides a simple way to set—up to any desired order—secular equations for the energy shifts and zeroth-order perturbed wavefunctions.

ISSN:0002-9505    

DOI:10.1119/1.1974198

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP

摘要:

An improved and simple undergraduate technique for determining the longitudinal spherical abberation (LSA) of a thin lens is described. It is shown that the results agree within 5% with the values calculated using the usual approximation made in the third-order aberration theory.

ISSN:0002-9505    

DOI:10.1119/1.1974199

出版商:American Association of Physics Teachers    

年代:1967

数据来源: AIP