摘要:

An advanced undergraduate laboratory experiment is described that employs a variation of the superconducting flux pump and commercially available magnetometer to measure the critical temperature, transition width, and the Meissner effect in type I superconductors in small external magnetic fields. The experiment is intended as an introduction to low-temperature techniques and to the magnetic properties and uses of superconductors.

ISSN:0002-9505    

DOI:10.1119/1.1986495

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

An attempt is made to clarify the physical and the mathematical reasonings that underlie Einstein's laws of gravitation. It appears that only by a mixture of physical reasonableness, mathematical simplicity, and aesthetic sensibility can one arrive at Einstein's field equations. The general theory of relativity is in fact an example of “the power of speculative thought.” The topics considered include a discussion of the principle of equivalence and the view of space-time as a geometric manifold. Two “derivations” of Einstein's equations are given: one based on physical reasonableness and the other based on a variational principle and mathematical simplicity.

ISSN:0002-9505    

DOI:10.1119/1.1986496

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

A computer augmented physics lab has been developed for the third-quarter introductory physics course in wave motion, sound, and light. New experiments are designed with application to interesting phenomena of the real world. The speed of sound and its temperature dependence are measured using time-of-flight techniques. Phenomena of reflection, refraction, diffraction, and anomalous propagation (mirage) are studied using the He-Ne laser. The computer is used to process and analyze experimental data and to extend experimental observations through simulation.

ISSN:0002-9505    

DOI:10.1119/1.1986497

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

A method is described for measuring the relativistic mass increase using simple, inexpensive equipment. The effect is large and easily seen.

ISSN:0002-9505    

DOI:10.1119/1.1986498

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

This experiment demonstrates that a charged particle moving through a magnetic field experiences a forceqv × B.When a saltwater solution flows through a magnetic field, the positive and negative ions are separated by the Lorentz force and establish an electric field. This field is measurable by means of the potential, or Hall voltage, developed across the flow tube.

ISSN:0002-9505    

DOI:10.1119/1.1986499

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

The problem of how to obtain a quantum equation of motion with higher derivatives is discussed. First the basic ideas of generalized classical mechanics with higher derivatives are reviewed. The generalized canonical conjugate momenta and a functionN,corresponding to the Hamiltonian function, are constructed. Then certain reduced momenta are introduced, which in absence of higher derivatives are identical to the canonical conjugate momenta. The functionNis expressed in terms of the reduced momenta. In order to obtain a quantum equation of motion, the reduced momenta inNare replaced by operators fulfilling some given conditions; thus the corresponding operatorN̂can be identified with the Hamiltonian operator. With its help, and introducing a wave function, the quantum equation of motion with higher derivatives is obtained.

ISSN:0002-9505    

DOI:10.1119/1.1986500

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

The transformation of the Hamiltonian of a charged particle from an inertial frame to a rotating frame in the presence of external electromagnetic fields is discussed.

ISSN:0002-9505    

DOI:10.1119/1.1986502

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

Aiming to develop from the introductory courses what can be called “physicist's skills,” we have employed a teaching strategy consisting mainly of independent study and small groups constantly supervised by the teaching staff. The Berkeley Physics Course is used as textbook, complemented with several laboratory experiments seeking the “discovery” rather than verification of physical laws.

ISSN:0002-9505    

DOI:10.1119/1.1986504

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

Simple inexpensive electrical analogs are described that illustrate the qualitative and quantitative behavior of wave motion on a one-dimensional monatomic lattice, a diatomic lattice, and on a lattice containing a defect.

ISSN:0002-9505    

DOI:10.1119/1.1986505

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP

摘要:

The construction, theory, and application of a simple Fourier-transform spectrometer for an undergraduate student laboratory experiment are described and illustrated. The instrument is a modified, commercially available, inexpensive Michelson interferometer, and the Fourier transform is produced by a time-shared computer, using a program inbasicbased on the Cooley-Tukey fast-Fourier-transform algorithm.

ISSN:0002-9505    

DOI:10.1119/1.1986506

出版商:American Association of Physics Teachers    

年代:1972

数据来源: AIP