摘要:

A formal device for evaluating integrals over the Fermi distribution function is presented. An expansion of the formal solution yields Sommerfeld's familiar result obtained in connection with the electron theory of metals. In special cases, the result can be expressed in closed form. One such case, the scattering form factor for the Fermi distribution, is presented. Application of the method to other integrals is indicated.

ISSN:0002-9505    

DOI:10.1119/1.1934430

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1934431

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

摘要:

An elementary experiment is described in which an object-image relationship for a thick lens is determined both by experiment and by calculations involving easily determined lens parameters. The two methods have over-all errors of less than 6% and agree quite well.

ISSN:0002-9505    

DOI:10.1119/1.1934432

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

摘要:

In the Planck radiation law the expression for energy density betweenλandλ+dλmay be divided byhc/λto give an expression for the number of photons per unit volume as a function ofλ. It is shown thatN = 20.30 cm−3 deg−3 T3, whereNis the number of photons percm3. The expressionsλnT = 0.3669 cm degandλaT = 0.5326 cm degare derived, whereλnis the wavelength at which the number of photons per unit volume betweenλandλ+dλis a maximum andλais the wavelength associated with the photon of average energy. The average energy per photon isEAv = 2.701 kT.

ISSN:0002-9505    

DOI:10.1119/1.1934433

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

摘要:

A teaching method is discussed whereby students solve mechanics problems which can be verified experimentally in the classroom. The verification is done by means of very simple equipment.

ISSN:0002-9505    

DOI:10.1119/1.1934434

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

摘要:

Professor Satterly recalls some of the incidents which have high-lighted a career of almost 60 years as a physicist and reminisces concerning the many famous physicists with whom he has studied and worked.

ISSN:0002-9505    

DOI:10.1119/1.1934435

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

摘要:

Charged, inflated, lighter-than-air rubber balloons moored by strings form a useful electroscope which can be viewed by a large audience. The balloons are out of the demonstrator's way and are not attracted to him or to other equipment. A calculation and a graph are given which permit the device to be used as a crude electrometer capable of detecting charges smaller than a microcoulomb.

ISSN:0002-9505    

DOI:10.1119/1.1934436

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

摘要:

The biographies of two groups of Fellows, 1137 from the 8th edition ofAmerican Men of Scienceand 300 others from the 9th, are examined geographically with respect to places of birth, of award of Ph.D. degree, and job. Age-number spectra are plotted for both groups. Academic origins of the smaller group are investigated.

ISSN:0002-9505    

DOI:10.1119/1.1934437

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1934438

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP

摘要:

A simple experimental setup, well adapted for demonstration purposes for the beginner and advanced student alike, vividly depicts current flow in insulators by holes or electrons. This is achieved by the trapping of carriers during electron or hole injection in alkali halides giving rise to striking color changes due to the formation of color centers.

ISSN:0002-9505    

DOI:10.1119/1.1934439

出版商:American Association of Physics Teachers    

年代:1957

数据来源: AIP