摘要:

Of the trio of famous papers that Albert Einstein sent to theAnnalen der Physikin 1905 only the paper proposing the photon concept has been unavailable in English translation. TheAmerican Journal of Physicsis publishing the following translation in recognition of the sixtieth anniversary of the appearance of the original work. Physics teachers may take particular interest in the following aspects: (1) Einstein's keen awareness of the heuristic character of his new conception. (2) His demonstration fromthermodynamicandstatisticalconsiderations that electromagnetic radiation might be conceived as consisting of finite numbers of discrete corpuscles of energyhv. (3) Hispredictionof the linear relation between the stopping potential of photoelectrons and the frequency of the incident light. This latter aspect of the photoelectric effect was not included among Lenard's early investigations. It remained for Millikan and others to develop the elegant experimental techniques that confirmed Einstein's bold prediction. Readers interested in pursuing the background in greater depth will find it rewarding to refer to the critical analyses by Martin J. Klein in “Einstein's First Paper on Quanta,” inThe Natural Philosopher(Blaisdell Publishing Company, New York, 1963), Vol. II, and “Einstein and the Wave-Particle Duality,” inThe Natural Philosopher, Vol. III, 1964. We are grateful to Professor Klein for his criticism and advice regarding this translation and for his generosity in making available to us an unpublished translation of his own.

ISSN:0002-9505    

DOI:10.1119/1.1971542

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

Explicit formulas, in terms of coordinate and momentum operators, are given for the parity operator and the Fourier-transform operator.

ISSN:0002-9505    

DOI:10.1119/1.1971546

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

This note supplements a previous note on the subject, and presents an alternative treatment, having independent interest, based on the infinitesimal transformations of the Lorentz group.

ISSN:0002-9505    

DOI:10.1119/1.1971549

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

A rapid error analysis of straight line plots can be performed in undergraduate laboratories by enclosing the data, in a parallelogram two of whose sides are parallel to the “best fit” line as determined by sight. Relatively little mathematical knowledge is needed for this method, so error analysis need not be ignored in elementary laboratories when straight line plots are made.

ISSN:0002-9505    

DOI:10.1119/1.1971553

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

A connection is made between geodesics on a curved, two-dimensional space-time surface and the trajectories of objects falling freely in straight paths in time-independent gravitationalfields. The treatment is presented on an elementary level, and the Einstein theory is not closely followed. Both geodesic motion and classical gravitation cause accelerations of objects whichare not influenced by the intrinsic properties of the object. The acceleration for geodesic motion is velocity as well as position dependent, whereas for classical gravitation, the accelerationdepends only on position. However, by the appropriate choice of scale, it is possible to approximate the classical trajectory with geodesic motion to any degree of accuracy. Geodesics on thesphere and cone are given as examples.

ISSN:0002-9505    

DOI:10.1119/1.1971555

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

The status of the Gibbs and Boltzmann expressions for entropy has been a matter of some confusion in the literature. We show that: (1) the GibbsHfunction yields the correct entropy as defined in phenomenological thermodynamics; (2) the BoltzmannHyields an “entropy” that is in error by a nonnegligible amount whenever interparticle forces affect thermodynamic properties; (3) Boltzmann's other interpretation of entropy,S = k log W, is consistent with the GibbsH, and derivable from it; (4) the BoltzmannHtheorem does not constitute a demonstration of the second law for dilute gases; (5) the dynamical invariance of the GibbsHgives a simple proof of the second law for arbitrary interparticle forces; (6) the second law is a special case of a general requirement for any macroscopic process to be experimentally reproducible. Finally, the “anthropomorphic” nature of entropy, on both the statistical and phenomenological levels, is stressed.

ISSN:0002-9505    

DOI:10.1119/1.1971557

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

Illustration of redistribution of impurities by zone-refining could be achieved by adding a colored, radioactive impurity to a bar of material and surveying the bar, before and afterpassing the zone, by a counting system. Stepwise details of the experiment are given. The main conclusions of the theory of zone-refining are summarized. Comparison between the experimentalresults and the theoretical predictions proved success of the zone-refining technique and demonstrated the advantage of using radioisotopes as a nondestructive means of analysis.

ISSN:0002-9505    

DOI:10.1119/1.1971559

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

摘要:

A simple derivation is presented for the quadratic index of refraction of scalar waves in a nonmagnetic medium.

ISSN:0002-9505    

DOI:10.1119/1.1971562

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1971566

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1971568

出版商:American Association of Physics Teachers    

年代:1965

数据来源: AIP