摘要:

A great number of good pendulum clocks have an accuracy of between ±0.1 and ±0.5 sec/day. This figure does not compare very well with the accuracy of a fairly good quartz-crystal clock, which can be of the order of 0.01 sec/day and better. Besides, setting a pendulum clock in the case that the difference in time is a fraction of its period is rather tedious.A method will be described by which a pendulum clock is locked into synchronization by energizing a pair of electromagnets (put at some critical places along the orbit of the pendulum) with special signals taken from a quartz-crystal clock.

ISSN:0002-9505    

DOI:10.1119/1.1953048

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

摘要:

The magnetic field distribution for a sphere in a uniform field is obtained by the usual method. This distribution is then transformed into the distribution for an ellipsoid in a uniform field by the method of conformal mapping.

ISSN:0002-9505    

DOI:10.1119/1.1934288

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

摘要:

With minor modifications, cutting and shaping one of the sides of the iron circuit, a core transformer can be made into a magnet. For example, one obtains a field strength of 6 kilogauss from such an electromagnet with a one-inch pole separation and a one-inch pole diameter. Using hollow pole pieces, it is possible to send a beam of microwaves through a paramagnetic sample placed between the poles inside a Dewar flask and to measure the microwave Faraday effect. The beam passes through the side walls of the oval-shaped flask. For 10 g ofMnSO4·4H2Othe absorption at the resonance point is 11, 26, and 30%; going through resonance the angle of rotation varies from plus to minus 1.9, 5.6, and 6.2 degrees for 290, 77, and 20°K, respectively.

ISSN:0002-9505    

DOI:10.1119/1.1934289

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

摘要:

The paper describes a simple theoretical model for explaining optical activity. The model consists of two anisotropic atoms, each having polarizabilityα. It is shown that when there is an assembly of such models, the refractive indices for right and left circular light are different, which means that the medium possesses optical rotatory power. By takingαto be complex in the vicinity of an optically active absorption band, the main features of Cotton effect or circular dichroism have also been explained.

ISSN:0002-9505    

DOI:10.1119/1.1934290

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

摘要:

The author would show that the political scientist is not sufficiently aware of what sciencequanatural science has done since the 16th century; that such an awareness is desirable at both the practical and theoretical levels of political enquiry; and that our colleges are capable of providing such an awareness, although they do not presently do so. He opposes “general education” programs, and proposes rigid course-work in fundamentals, including the calculus.

ISSN:0002-9505    

DOI:10.1119/1.1934291

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

摘要:

The development of the algebra of quaternions is reviewed and discussed from a modern viewpoint stressing their aspect as 4-vectors and their educational value to the student of physics. Their relationship to 3-vectors, tensors, and complex matrices is noted. Geometrical visualization of their properties is developed. Their application to problems of polarized radiation and special relativity is described.

ISSN:0002-9505    

DOI:10.1119/1.1934292

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1934293

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1934294

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1934295

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1934296

出版商:American Association of Physics Teachers    

年代:1956

数据来源: AIP