摘要:

This note demonstrates how the principle of conservation of energy can be used to derive in a simple and correct way the Shockley-Ramo equation for currents induced by charged particles in electronic devices. The simplest form of this equation occurs for a chargeqwhich moves with speedvbetween two plane-parallel electrodes separated by a distanced. For this case the induced currentIis given byI = qv/d. A one-dimensional example, for which the calculations are quite simple, is considered in detail by the energy method.

ISSN:0002-9505    

DOI:10.1119/1.1972306

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

An instrument and its utilization are described which provides for study of several aspects of sound waves. Basically the instrument consists of a pair of telescoping plastic tubes. The inner tube has one end closed by a removable plug containing a built-in microphone. A speaker whose diameter conforms to that of the outer tube is driven by an audio oscillator.O-ring seals are used to confine the major portion of the sound energy inside the tubes. Acoustical phenomena observable include: closed and open-tube resonance, longitudinal nature of sound waves and limitations of mechanical resonance of particles such as cork dust, use of Lissajous figures to observe phase variation of wave as a function of distance from source and to locate resonance positions with increased precision, excitation of various modes of vibration and analysis thereof with a frequency counter, and absorption of sound energy.

ISSN:0002-9505    

DOI:10.1119/1.1972309

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

Elementary vector and matrix methods are used to prove several fundamental theorems that bear on the foundation of kinematics of finite, rigid-body displacements. Euler's theorem, the parallel axis theorem, invariance of axial projected displacements, Chasles' theorem, and other equivalent displacement theorems are proved. The composition of several screw displacements is investigated, and it is shown that the resultant screw is unique.

ISSN:0002-9505    

DOI:10.1119/1.1972311

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

A new Atwood's machine attachment has been designed in which one side of the system consists of a drum around which the string is wrapped so that the drum rotates as it falls. The other side of the system consists of a falling body, whose mass can be varied. Two sparktimer records are taken, one for the drum, and one for the falling body. Data taken are used to verify the law of motion of the mass center and the law of motion about the mass center.

ISSN:0002-9505    

DOI:10.1119/1.1972313

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

It is shown that an appropriate formulation of the uncertainty principle for normal operators leads to the same mathematical expression as that for Hermitian operators. The treatment is valid for mixed states as well as for pure states.

ISSN:0002-9505    

DOI:10.1119/1.1972318

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

A rugged lecture and laboratory apparatus is described with which it is possible to obtain data and plot a hysteresis loop in only a few minutes.

ISSN:0002-9505    

DOI:10.1119/1.1972324

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

The four quadratic constants of the motion for the two dimensional classical harmonic oscillator are examined. Although all four are needed for closure under the operation of Poisson bracketing, the values of three determine the trajectories. A physical meaning and a method of measurement are obtained for the fourth COM,P = q1q2+p1p2, which is found to be a difference of energies measured in a rotated coordinate system. The study is simplified for the two dimensional harmonic oscillator by the use of matrix block multiplication and the use of the correspondence between the multiplication of certain matrices and the multiplication of complex numbers; the simplification is even greater when this easy formalism is extended to thendimensional case. Inndimensions, ifPkj = qkqj+pkpjandLkj = qkpj−pkqj, then thePkj+iLkjprovide a basis for a space isomorphic to that ofnbynhermitian matrices, the generators of the group SUn. As in two dimensions, thePkjcan be identified as partial energies. Then2linearly independent COM are redundant:2n−1determine the orbit uniquely.

ISSN:0002-9505    

DOI:10.1119/1.1972328

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

Partial coherence theory is used to describe Fourier spectroscopy. It is shown that the resolving power is of the formrm/aλwith the value ofadepending upon the coherence time of the radiation. The effect of spatial coherence upon the experiment is considered as well as the continuous variation of the delay time. No effects of data processing are considered.

ISSN:0002-9505    

DOI:10.1119/1.1972333

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

摘要:

A number of interesting sketches of the Carnot cycle (operated as a heat engine and with an ideal gas as the working substance) are presented. Heat and work are used as the coordinates in addition to several thermodynamic variables (P, V, T, E, H, S, G, and A). The teaching value of such diagrams is stressed as some characteristics of the diagrams are pointed out.

ISSN:0002-9505    

DOI:10.1119/1.1972338

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1972342

出版商:American Association of Physics Teachers    

年代:1966

数据来源: AIP