摘要:

Some results of interest in quantum measurement theory are derived from a consideration of a collision between two one-dimensional Gaussian wave packets. Relationships are found between the momentum and position uncertainties of the packets before and after the collision. It is shown that the coordinates of a poorly defined packet can be better defined by causing it to collide with a well-defined packet. A classical analog is presented in which the same results are obtained.

ISSN:0002-9505    

DOI:10.1119/1.1969918

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

摘要:

An advanced undergraduate laboratory experiment which studies the response of a bar to forced transverse vibrations is described. The amplitude and phase of vibration are monitored using a relatively simple optical system involving Moire fringes. Light is passed through two Ronchi rulings onto a photocell, the photocell output being a direct measure of the phase and the amplitude of vibration. The photocell output and the oscillator voltage used to drive the bar can be applied to the vertical and horizontal input, respectively, of an oscilloscope to produce Lissajous figures. These figures can then be studied and related to the properties of forced vibration. Typical results for resonance curves with and without external damping are given.

ISSN:0002-9505    

DOI:10.1119/1.1969921

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

摘要:

The forces acting on a body, and its position of equilibrium, in a uniform magnetic or electric field are determined by the free energy and not by the field energy. Incorrect results are obtained if the field energy is used as a potential function since the work done in a virtual displacement on the distant sources of the field is not taken into account. The net-energy flux that results from a virtual displacement of a body is calculated here and the free energy is determined. It is shown that the flux of the Poynting vector cannot be neglected in this case even though quasistatic processes are involved. The results are illustrated by the example of a paramagnetic or a diamagnetic ellipsoid in a uniform magnetic field.

ISSN:0002-9505    

DOI:10.1119/1.1969923

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

摘要:

The transient compressional stresses generated in solid bodies by impulsive loading provide an excellent vehicle for demonstrating to elementary students the physical character and implications of wave velocity, particle velocity, wave boundary conditions, and momentum partitioning. This paper suggests how some of these ideas can be presented.

ISSN:0002-9505    

DOI:10.1119/1.1969926

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

摘要:

Editors Note:As a result of support by Addison-Wesley Publishing Company, the American Association of Physics Teachers has established an annual lectureship, named in honor of Robert A. Millikan. It is anticipated that this will bring to each summer meeting of the Association a physicist who will speak on a topic of current interest and that the summer meeting will thus have a feature comparable with the Richtmyer Lecture at the annual meeting. The committee responsible for the first Millikan Lecture chose H. V. Neher, long time associate of Millikan. This highly suitable choice was as appropriate as was Neher's choice of a topic—Millikan himself. The editors of theAmerican Journal of Physicsare grateful for permission to publish this pleasantly informal biographical lecture, spiced as it is with personal reminiscences.

ISSN:0002-9505    

DOI:10.1119/1.1969929

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

摘要:

A laboratory experiment is described which demonstrates the equivalence of potential energy and work to an accuracy of several per cent through the use of two magnets.

ISSN:0002-9505    

DOI:10.1119/1.1969932

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

摘要:

Certain experimental phenomena, like the homopolar generator, whose analyses have caused confusion are shown to be understandably treated by the following: Use the differential form of Maxwell's four field relations together with the Lorentz force equation as the fundamental relations for treating all electromagnetic phenomena in the observer's coordinate system. The Lorentz force is considered to act on all of the charges in any material body moving in magnetic fields in these coordinates. Faraday's lawε = −dΦ/dt, becomes a derived through very useful relation. This system provides revealing Poynting vector for all steady-state energy conversions.

ISSN:0002-9505    

DOI:10.1119/1.1969936

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

摘要:

When a prism with three polished faces is used on a spectrometer, because of partial internal reflection, light eventually emerges from all three faces of the prism. It is shown that, in general, there are only two directions of emergence from each face. From the face of incidence one of these directions is uniquely that of the externally reflected light. The two emergent beams from any face are unequally dispersed, and in certain circumstances one may be undispersed (one of the beams from the face of incidence is always of this character). In such circumstances the undispersed beam coincides in direction with each component of the dispersed beam when that component is at minimum deviation. This property provides an accurate method of adjustment for minimum deviation. When this method is used in practice, there are important advantages to be gained by heavily silvering two of the prism faces and making observations on the spectrum observed in a telescope directed towards the unsilvered face of incidence.

ISSN:0002-9505    

DOI:10.1119/1.1969940

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1969947

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1969949

出版商:American Association of Physics Teachers    

年代:1964

数据来源: AIP