摘要:

The correction for finite impedance of thermocouple instrumentation is derived rigorously from irreversible thermodynamics. Also, the indistinguishability of Peltier and Thomson “emf's” is elucidated.

ISSN:0002-9505    

DOI:10.1119/1.1973110

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

The construction and operation of a simple apparatus for optical pumping experiments using rubidium vapor are described. The experiments are intended to involve students with the concepts of resonance, atomic orientation, nuclear magnetic moments, and the precession of atomic magnetic moments. An outline of the elementary theory is included.

ISSN:0002-9505    

DOI:10.1119/1.1973111

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

A student experiment with free precession of rubidium atoms is described which uses the simple apparatus for optical pumping experiments described in Part I of this paper. This experiment shows that an oriented ensemble of atoms may be treated as a macroscopic magnetized gyroscope.

ISSN:0002-9505    

DOI:10.1119/1.1973112

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

The torque on a rigid body in circular orbit in a gravitational central field is derived, using the body-centered coordinate system aligned with the gravity gradient vector. Application of the general result to the special cases of pure pitch, roll, and yaw rotations is considered. From these cases, the orientations of stable equilibrium are deduced.

ISSN:0002-9505    

DOI:10.1119/1.1973113

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

The equation of motion for a relativistic rocket or for any particle with a variable rest mass may be derived by applying the relativistic impulse-momentum and work-energy principles in the instantaneous rest frame. The equation of motion in this frame is in the classical non-relativistic form. The equation of motion in the observer's rest frame may then be deduced by applying the relativistic transformation equations for velocity, force, and time.

ISSN:0002-9505    

DOI:10.1119/1.1973114

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

A brief discussion is given of force-free magnetic fields generated by two systems of mutually orthogonal currents in a homogeneous and unbounded conducting fluid. Rectangular, cylindrical, and spherical force-free field solutions are presented as examples illustrating the problem.

ISSN:0002-9505    

DOI:10.1119/1.1973115

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

In the physics and mathematics literature there exist two undetermined multiplier treatments of the Lagrange problem of the calculus of variations. These two treatments yield different results, in general; although they are in agreement in several commonly treated special cases. It is shown herein that the method favored by most physics texts is incorrect in the case of nonintegrable differential constraints, while the method appearing in most books on the methods of mathematical physics and the calculus of variations is correct, in general.

ISSN:0002-9505    

DOI:10.1119/1.1973116

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

Boltzmann's constant, the charge on the electron and the centigrade temperature of absolute zero are measured in the experiment described. Details of the apparatus, which has given good results in the hands of students and which can be constructed from standard electronic components, are given.

ISSN:0002-9505    

DOI:10.1119/1.1973117

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

A special form of construction for electron devices is described. This construction makes it possible to assemble a wide range of apparatus from inexpensive standard parts, without the use of tools. Modifications can be made with particular ease because the electrodes can be installed, repositioned or removed independently of one another. These features make the apparatus convenient for use in undergraduate and graduate laboratory projects, as well as in more advanced research applications. Examples are given of some typical assemblies, ranging from simple electron emitters to cathode-ray tubes, electron multipliers, and a complete mass spectrometer.

ISSN:0002-9505    

DOI:10.1119/1.1973118

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

Mach's reinterpretation of Newtonian mechanics is examined and found ambivalent. His criticism of absolute time and absolute space was sound whereas his attempt to replace Newton's whole theory by an allegedly empirical statement and a definition was logically untenable. The whole program of reducing mechanics to kinematics is found to be unfeasible for logical reasons. The impossibility of deriving masses and forces from observations alone is discussed in detail. The driving force behind Mach's ideas on the foundations of mechanics is shown to be his empiricist philosophy which, while allowing him to impugn inscrutables, also suggested him to minimize the role of ideas. It is recalled that the discussion of the foundations of mechanics proceeds nowadays in a way far removed from Mach's operationalistic approach, namely via the axiomatic reconstruction of classical theories on the basis of undefined but meaningful concepts.

ISSN:0002-9505    

DOI:10.1119/1.1973119

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP