摘要:

Editor’snote: Remarks made by H. Richard Crane upon receipt of the 1976 Oersted Medal. Bestowed by the American Association of Physics Teachers ’’for notable contributions to physics education,’’ the Medal was presented to Professor Crane at the ceremonial session of the joint meeting of the American Physical Society and the American Association of Physics Teachers, Chicago, Illinois, 7–10 February 1977. [See J. B. Guernsey, Am. J. Phys. 45, 507 (1977), for remarks made in presenting the Medal.]

ISSN:0002-9505    

DOI:10.1119/1.10810

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

The uses of silicon solar cells as subjects of experiments in undergraduate teaching laboratories are discussed. The basic theory of these cells is presented, including equivalent circuits and characteristic equations. Fundamental experiments on the power output and efficiency, which are appropriate for non‐science majors’ courses, are detailed, as well as more advanced experiments on cell parameters. Experimental results and agreement with theory are presented for a typical inexpensive cell.

ISSN:0002-9505    

DOI:10.1119/1.10811

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

We consider two‐dimensional motion of a projectile experiencing a constant gravitational force and a fluid drag force which is quadratic in the projectile’s speed. The equations of motions are coupled nonlinear equations. Their solutions have general properties which are easily visualized, although much different from those obtained when a drag force is neglected. Because of these features a study of these equations would provide an interesting counterpoint to the already familiar case of no drag. In this paper we derive simple approximate solutions to the equations of motion for both short and long times. A numerical example is used to compare these approximate solutions with accurate results obtained by numerical integration from an exact but implicit solution. Finally, the origin of the quadratic drag force is discussed.

ISSN:0002-9505    

DOI:10.1119/1.10812

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

The departure of the electrongfactor from 2 is calculated using a nonrelativistic theory of the electron interacting with the quantized transverse electromagnetic field. Although the magnetic moment correction δμ, due to the radiation field, is antiparallel to the magnetic moment μ0of the bare electron, it is shown that thegfactor correction is positive for a reasonable cutoff. This is due to the fact that thegfactor is defined as the magnetic moment in units of the ’’physical’’ Bohr magneton. The role of mass renormalization is emphasized in this approach, and it is shown that the experimentalgfactor emerges for a cutoff of 0.53 electron masses.

ISSN:0002-9505    

DOI:10.1119/1.10814

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

We introduce the concept of equivalent volume charge density for all types of charge and multipole distributions, discrete as well as continuous. The equivalent volume charge density for point charges, point dipoles, and point quadrupoles is expressed in terms of the Dirac delta function and its derivatives. The equivalent volume charge density for surface charge distributions and surface dipole distributions is obtained by introducing a ’’surface delta function.’’ The well‐known equivalence between a continuous distribution of dipoles within a specified volume and the volume and surface densities is derived directly by means of the delta function formalism. The same method is also applied to find the equivalent volume and charge distributions for a continuous distribution of quadrupoles confined in a specified volume.

ISSN:0002-9505    

DOI:10.1119/1.10779

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

It is shown that investigating Coriolis effects in the fixed frame leads to a clearer understanding of their physical nature: the body carries along its initial velocity, larger or smaller than the velocity of its corresponding point during the motion. A simple but thorough calculation of some effects (the Foucault pendulum and the eastward drift of a falling body) is given.

ISSN:0002-9505    

DOI:10.1119/1.10780

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

A simple geometrical means of visualizing and generating families of Rayleigh magnetic hysteresis loops is presented.

ISSN:0002-9505    

DOI:10.1119/1.10781

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

The popular rotating chair and hand‐held weights demonstration on the conservation of angular momentum has been adapted to the lower division laboratory. The demonstration has been made quantitative by adding radial tracks to the chair along which calibrated masses may be positioned without extension of the occupant’s arms. The conservation of angular momentum can be tested and the moment of inertia of the student in various sitting positions can be determined.

ISSN:0002-9505    

DOI:10.1119/1.10782

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

An undergraduate experiment investigating the polarization characteristics of light scattered from a dielectric cylinder is presented. Students generally find the results surprising; however, the observations support the predictions of classical electromagnetic theory.

ISSN:0002-9505    

DOI:10.1119/1.10799

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

Properties of an infinitely long, linear array of atoms are described assuming the atoms interact with each other via a Morse pairwise potential. The equilibrium lattice parameter for a regularly spaced array is calculated, as is the potential function pertinent to vacancy migration. A specific numerical example is considered using the Girifalco and Weizer parameters for the pairwise interatomic potential characterizing body‐centered‐cubic iron.

ISSN:0002-9505    

DOI:10.1119/1.10800

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP