ISSN:0002-9505    

DOI:10.1119/1.17788

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18077

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17793

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17795

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18066

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17798

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17764

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

Details are given for the construction of a 70‐cm‐long Foucault pendulum to be mounted on the wall, and for a simple modification that will make it display local clock time. The possibility of having a Foucault pendulum of such short length is the result of finding new or improved ways of reducing four perturbing effects that become more severe as the length is decreased. They relate to: precession due to ellipticity in the motion, the drive system for maintaining the amplitude, the means of limiting the growth of ellipticity, and the method of gripping the suspending wire at the top. With those improvements, successful Foucault operation was attained in pendulums as short as 15 cm, support to center of bob. Following that severe test, the length for the ‘‘wall clock’’ was set at a conservative 70 cm. At that length it is highly reliable, and accurate to within 2% when timed for the full revolution. Uniformity in rate when comparing different intervals of azimuth is of course less. A simple method of making the pendulum read local time is described. Two clocks, one in the author’s office and one at home, have been in continuous operation for more than ten years.

ISSN:0002-9505    

DOI:10.1119/1.17765

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

Students in our upper‐division/graduate optics laboratory course assemble a Mach–Zehnder interferometer from simple components and use it to learn about interferometric principles and to visualize the phase‐front geometries of light waves. Here we describe the experimental procedures, specify the equipment needed, and make suggestions for follow‐up experiments.

ISSN:0002-9505    

DOI:10.1119/1.17766

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

Using minimal formalism, we demonstrate that the massless photons, constituting the radiation in a cavity, contribute to the mass of the cavity in agreement with Einstein’s mass–energy formula. We assume that a photon has energy and momentum related to frequency byE=hν,p=hν/c. Restricting velocities to nonrelativistic values, we impart a uniform acceleration to the cavity. Reflection from a moving mirror produces a Doppler shift, and thus the momentum delivered to the front and rear walls can easily be calculated in the laboratory frame. A simple application ofF=maleads to the usual conclusion that the mass of a gas of photons of total energyUisU/c2. An alternative argument based on calculations in the co‐accelerating frame is also given.

ISSN:0002-9505    

DOI:10.1119/1.17767

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP