摘要:

A range of experiments in heat conduction suitable for upper level undergraduate laboratories are described. The experiments progressively cover situations of increasing theoretical complexity. The experiments are relatively easy to perform and make use of heat sensitive liquid crystal film to measure temperature contours. The initial experiments cover examples of situations where Laplace’s equation is applicable and can be used to complement experiments in electrostatics using resistive paper. The remaining experiments extend the investigations to situations where Poisson’s equation and the diffusion equation are applicable. In these latter two cases the liquid crystal film serves as the heat conduction medium in addition to its function as a temperature sensor. For the diffusion equation situation a video camera is used in conjunction with the liquid crystal film.

ISSN:0002-9505    

DOI:10.1119/1.18082

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

This article describes lecture demonstration apparatus for displaying free and forced oscillations of a mechanical system to a large class. The setup described won first prize at the AAPT apparatus competition in August 1994. A Plexiglas blade clamped at one end is magnetically driven by a low‐frequency generator–amplifier. The frequencies are so low (between 0.2 and 1.2 Hz) that visual observations of displacements are possible. The driving voltage, associated with the force applied, is visualized with a row of 20 light‐emitting diodes, a laser pointer projecting displacements, and a photosensor providing sound cues for phase references. Dependence of amplitude and phase on frequency can be seen, heard, and recorded by a large group of students. The apparatus is simple enough to be replicated and used at all levels of physics teaching. Technical details on the LED display unit, and some theoretical considerations, are described in two appendices.

ISSN:0002-9505    

DOI:10.1119/1.17921

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

Thermodynamic properties of nonrelativistic bosons and fermions in two spatial dimensions and without interactions are derived. All the virial coefficients are the same except for the second, for which the signs are opposite. This results in the same specific heat for the two gases. Existing equations of state for the free anyon gas are also discussed and shown to break down at low temperatures or high densities.

ISSN:0002-9505    

DOI:10.1119/1.17922

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17923

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17924

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18083

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17925

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17926

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP