摘要:

Although the general properties of the phase shift of the three‐dimensional spherically symmetrical square well potential are described in most textbooks on quantum mechanics, specific graphical representations of this function are rare. In this paper we present a number of phase shifts, as a function of energy, for the various values of the angular momentum quantum number. We discuss the general features of these curves. In particular, we consider what happens to the phase shifts if one varies the depth of the well, not only for near‐zero energy, but for the entire range of energies. We describe how the bound levels of a deep well are related to the virtual levels of the shallow well. We find points of triple coincidence for curves belonging to three successive l values for given well depth. A proof of this phenomenon is given.

ISSN:0002-9505    

DOI:10.1119/1.9806

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

We present in this paper a derivation of the Lorentz transformation by invoking the principle of relativity alone, without resorting to the a priori assumption of the existence of a universal limiting velocity. Such a velocity is shown to be a necessary consequence of the first postulate, and the fact that it is not infinite is borne out by experiment.

ISSN:0002-9505    

DOI:10.1119/1.9807

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

An astronaut in the vicinity of an orbiting spacecraft must navigate himself by means of impulsive velocity changes Δv, imparted by hands or feet or by small rockets. The motion relative to the spacecraft produced by such an impulse is noticeably nonlinear; if ejected from the spacecraft with a typical Δv of magnitude 2 m/sec in the orbital plane of the spacecraft, the astronaut suffers a net transverse deflection of 22.5 cm after 10 sec. Celestial mechanics can give only a numerical solution, which is of little practical help to the astronaut. In this paper we present approximate closed‐form solutions valid for low speeds (≲100 m/sec) and short elapsed times (≲0.1 orbital period), for a Skylab‐like Earth orbit of semimajor axis 6800 km.

ISSN:0002-9505    

DOI:10.1119/1.9821

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

This paper discusses and illustrates the use of loci in the complex plane to illuminate the behavior of steady‐state ac circuits. Phase and amplitude dependence on a chosen parameter are illustrated with twelve examples.

ISSN:0002-9505    

DOI:10.1119/1.9822

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

It is demonstrated that a commom microscopic model of a resistor exhibits a reactive component of the admittance which dominates at sufficiently high frequencies and causes a decrease in the noise spectral density of the current fluctuations. In addition, Nyquist’s theorem is derived for the general classical case including the coulomb interactions between the carriers and the influence of the lattice potential. The significance of the real part of the admittance is made apparent directly.

ISSN:0002-9505    

DOI:10.1119/1.9823

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

Students investigate in the introductory laboratory the relationship between distance from a light source and illuminance. A graphical display and analysis of data leads to the ’’discovery’’ of the inverse square law. Its validity is confirmed by excellent agreement between predicted and observed values. A 12‐V high‐intensity bulb is used as a point source; the detector is an inexpensive silicon photocell connected to a milliammeter. The assumption of a point source requirement is tested by the use of a diffusing screen.

ISSN:0002-9505    

DOI:10.1119/1.9824

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.9825

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.9826

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.9828

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.9829

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP