1 CHAPTER 16 CGS ELECTRICITY and MAGNETISM 16.1 Introduction We Are Accustomed to Using MKS (Metre-Kilogram-Second) Units
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On the First Electromagnetic Measurement of the Velocity of Light by Wilhelm Weber and Rudolf Kohlrausch
Andre Koch Torres Assis On the First Electromagnetic Measurement of the Velocity of Light by Wilhelm Weber and Rudolf Kohlrausch Abstract The electrostatic, electrodynamic and electromagnetic systems of units utilized during last century by Ampère, Gauss, Weber, Maxwell and all the others are analyzed. It is shown how the constant c was introduced in physics by Weber's force of 1846. It is shown that it has the unit of velocity and is the ratio of the electromagnetic and electrostatic units of charge. Weber and Kohlrausch's experiment of 1855 to determine c is quoted, emphasizing that they were the first to measure this quantity and obtained the same value as that of light velocity in vacuum. It is shown how Kirchhoff in 1857 and Weber (1857-64) independently of one another obtained the fact that an electromagnetic signal propagates at light velocity along a thin wire of negligible resistivity. They obtained the telegraphy equation utilizing Weber’s action at a distance force. This was accomplished before the development of Maxwell’s electromagnetic theory of light and before Heaviside’s work. 1. Introduction In this work the introduction of the constant c in electromagnetism by Wilhelm Weber in 1846 is analyzed. It is the ratio of electromagnetic and electrostatic units of charge, one of the most fundamental constants of nature. The meaning of this constant is discussed, the first measurement performed by Weber and Kohlrausch in 1855, and the derivation of the telegraphy equation by Kirchhoff and Weber in 1857. Initially the basic systems of units utilized during last century for describing electromagnetic quantities is presented, along with a short review of Weber’s electrodynamics. -
Electric Units and Standards
DEPARTMENT OF COMMERCE OF THE Bureau of Standards S. W. STRATTON, Director No. 60 ELECTRIC UNITS AND STANDARDS list Edition 1 Issued September 25. 1916 WASHINGTON GOVERNMENT PRINTING OFFICE DEPARTMENT OF COMMERCE Circular OF THE Bureau of Standards S. W. STRATTON, Director No. 60 ELECTRIC UNITS AND STANDARDS [1st Edition] Issued September 25, 1916 WASHINGTON GOVERNMENT PRINTING OFFICE 1916 ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, D. C. AT 15 CENTS PER COPY A complete list of the Bureau’s publications may be obtained free of charge on application to the Bureau of Standards, Washington, D. C. ELECTRIC UNITS AND STANDARDS CONTENTS Page I. The systems of units 4 1. Units and standards in general 4 2. The electrostatic and electromagnetic systems 8 () The numerically different systems of units 12 () Gaussian systems, and ratios of the units 13 “ ’ (c) Practical ’ electromagnetic units 15 3. The international electric units 16 II. Evolution of present system of concrete standards 18 1. Early electric standards 18 2. Basis of present laws 22 3. Progress since 1893 24 III. Units and standards of the principal electric quantities 29 1. Resistance 29 () International ohm 29 Definition 29 Mercury standards 30 Secondary standards 31 () Resistance standards in practice 31 (c) Absolute ohm 32 2. Current 33 (a) International ampere 33 Definition 34 The silver voltameter 35 ( b ) Resistance standards used in current measurement 36 (c) Absolute ampere 37 3. Electromotive force 38 (a) International volt 38 Definition 39 Weston normal cell 39 (b) Portable Weston cells 41 (c) Absolute and semiabsolute volt 42 4. -
Guide for the Use of the International System of Units (SI)
Guide for the Use of the International System of Units (SI) m kg s cd SI mol K A NIST Special Publication 811 2008 Edition Ambler Thompson and Barry N. Taylor NIST Special Publication 811 2008 Edition Guide for the Use of the International System of Units (SI) Ambler Thompson Technology Services and Barry N. Taylor Physics Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 (Supersedes NIST Special Publication 811, 1995 Edition, April 1995) March 2008 U.S. Department of Commerce Carlos M. Gutierrez, Secretary National Institute of Standards and Technology James M. Turner, Acting Director National Institute of Standards and Technology Special Publication 811, 2008 Edition (Supersedes NIST Special Publication 811, April 1995 Edition) Natl. Inst. Stand. Technol. Spec. Publ. 811, 2008 Ed., 85 pages (March 2008; 2nd printing November 2008) CODEN: NSPUE3 Note on 2nd printing: This 2nd printing dated November 2008 of NIST SP811 corrects a number of minor typographical errors present in the 1st printing dated March 2008. Guide for the Use of the International System of Units (SI) Preface The International System of Units, universally abbreviated SI (from the French Le Système International d’Unités), is the modern metric system of measurement. Long the dominant measurement system used in science, the SI is becoming the dominant measurement system used in international commerce. The Omnibus Trade and Competitiveness Act of August 1988 [Public Law (PL) 100-418] changed the name of the National Bureau of Standards (NBS) to the National Institute of Standards and Technology (NIST) and gave to NIST the added task of helping U.S. -
S.I. and Cgs Units
Some Notes on SI vs. cgs Units by Jason Harlow Last updated Feb. 8, 2011 by Jason Harlow. Introduction Within “The Metric System”, there are actually two separate self-consistent systems. One is the Systme International or SI system, which uses Metres, Kilograms and Seconds for length, mass and time. For this reason it is sometimes called the MKS system. The other system uses centimetres, grams and seconds for length, mass and time. It is most often called the cgs system, and sometimes it is called the Gaussian system or the electrostatic system. Each system has its own set of derived units for force, energy, electric current, etc. Surprisingly, there are important differences in the basic equations of electrodynamics depending on which system you are using! Important textbooks such as Classical Electrodynamics 3e by J.D. Jackson ©1998 by Wiley and Classical Electrodynamics 2e by Hans C. Ohanian ©2006 by Jones & Bartlett use the cgs system in all their presentation and derivations of basic electric and magnetic equations. I think many theorists prefer this system because the equations look “cleaner”. Introduction to Electrodynamics 3e by David J. Griffiths ©1999 by Benjamin Cummings uses the SI system. Here are some examples of units you may encounter, the relevant facts about them, and how they relate to the SI and cgs systems: Force The SI unit for force comes from Newton’s 2nd law, F = ma, and is the Newton or N. 1 N = 1 kg·m/s2. The cgs unit for force comes from the same equation and is called the dyne, or dyn. -
SI and CGS Units in Electromagnetism
SI and CGS Units in Electromagnetism Jim Napolitano January 7, 2010 These notes are meant to accompany the course Electromagnetic Theory for the Spring 2010 term at RPI. The course will use CGS units, as does our textbook Classical Electro- dynamics, 2nd Ed. by Hans Ohanian. Up to this point, however, most students have used the International System of Units (SI, also known as MKSA) for mechanics, electricity and magnetism. (I believe it is easy to argue that CGS is more appropriate for teaching elec- tromagnetism to physics students.) These notes are meant to smooth the transition, and to augment the discussion in Appendix 2 of your textbook. The base units1 for mechanics in SI are the meter, kilogram, and second (i.e. \MKS") whereas in CGS they are the centimeter, gram, and second. Conversion between these base units and all the derived units are quite simply given by an appropriate power of 10. For electromagnetism, SI adds a new base unit, the Ampere (\A"). This leads to a world of complications when converting between SI and CGS. Many of these complications are philosophical, but this note does not discuss such issues. For a good, if a bit flippant, on- line discussion see http://info.ee.surrey.ac.uk/Workshop/advice/coils/unit systems/; for a more scholarly article, see \On Electric and Magnetic Units and Dimensions", by R. T. Birge, The American Physics Teacher, 2(1934)41. Electromagnetism: A Preview Electricity and magnetism are not separate phenomena. They are different manifestations of the same phenomenon, called electromagnetism. One requires the application of special relativity to see how electricity and magnetism are united. -
DIMENSIONS and UNITS to Get the Value of a Quantity in Gaussian Units, Multiply the Value Ex- Pressed in SI Units by the Conversion Factor
DIMENSIONS AND UNITS To get the value of a quantity in Gaussian units, multiply the value ex- pressed in SI units by the conversion factor. Multiples of 3 intheconversion factors result from approximating the speed of light c =2.9979 1010 cm/sec × 3 1010 cm/sec. ≈ × Dimensions Physical Sym- SI Conversion Gaussian Quantity bol SI Gaussian Units Factor Units t2q2 Capacitance C l farad 9 1011 cm ml2 × m1/2l3/2 Charge q q coulomb 3 109 statcoulomb t × q m1/2 Charge ρ coulomb 3 103 statcoulomb 3 3/2 density l l t /m3 × /cm3 tq2 l Conductance siemens 9 1011 cm/sec ml2 t × 2 tq 1 9 1 Conductivity σ siemens 9 10 sec− 3 ml t /m × q m1/2l3/2 Current I,i ampere 3 109 statampere t t2 × q m1/2 Current J, j ampere 3 105 statampere 2 1/2 2 density l t l t /m2 × /cm2 m m 3 3 3 Density ρ kg/m 10− g/cm l3 l3 q m1/2 Displacement D coulomb 12π 105 statcoulomb l2 l1/2t /m2 × /cm2 1/2 ml m 1 4 Electric field E volt/m 10− statvolt/cm t2q l1/2t 3 × 2 1/2 1/2 ml m l 1 2 Electro- , volt 10− statvolt 2 motance EmfE t q t 3 × ml2 ml2 Energy U, W joule 107 erg t2 t2 m m Energy w, ϵ joule/m3 10 erg/cm3 2 2 density lt lt 10 Dimensions Physical Sym- SI Conversion Gaussian Quantity bol SI Gaussian Units Factor Units ml ml Force F newton 105 dyne t2 t2 1 1 Frequency f, ν hertz 1 hertz t t 2 ml t 1 11 Impedance Z ohm 10− sec/cm tq2 l 9 × 2 2 ml t 1 11 2 Inductance L henry 10− sec /cm q2 l 9 × Length l l l meter (m) 102 centimeter (cm) 1/2 q m 3 Magnetic H ampere– 4π 10− oersted 1/2 intensity lt l t turn/m × ml2 m1/2l3/2 Magnetic flux Φ weber 108 maxwell tq t m m1/2 Magnetic -
Automatic Irrigation : Sensors and System
South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange Electronic Theses and Dissertations 1970 Automatic Irrigation : Sensors and System Herman G. Hamre Follow this and additional works at: https://openprairie.sdstate.edu/etd Recommended Citation Hamre, Herman G., "Automatic Irrigation : Sensors and System" (1970). Electronic Theses and Dissertations. 3780. https://openprairie.sdstate.edu/etd/3780 This Thesis - Open Access is brought to you for free and open access by Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]. AUTOMATIC IRRIGATION: SENSORS AND SYSTEM BY HERMAN G. HAMRE A thesis submitted in partial fulfillment of the requirements for the degree Master of Science, Major in Electrical Engineering, South Dakota State University 1970 SOUTH DAKOTA STATE UNIVERSITY LIBRARY AUTOMATIC IRRIGATION: SENSORS AND SYSTEM This thesis is approved as a creditable and independent investi gation by a candidate for the degree, Master of Science, and is accept able as meeting the thesis requirements for this degree, but without implying that the conclusions reached by the candidate are necessarily the conclusions of the major department. �--- -"""'" _ _ -���--- - _ _ _ _____ -A>� - 7 7 T b � s/./ifjvisor ate Head, Electrical -r-oate Engineering Department ACKNOWLE GEMENTS The author wishes to express his sincere appreciation to Dr. A. J. Kurtenbach for his patient guidance and helpful suggestions, and to the Water Resources Institute for their support of this research. -
20 Coulomb's Law Of
Coulomb’s Law of 20 Electrostatic Forces Charge Interactions Are Described by Coulomb’s Law Electrical interactions between charges govern much of physics, chemistry, and biology. They are the basis for chemical bonding, weak and strong. Salts dis- solve in water to form the solutions of charged ions that cover three-quarters of the Earth’s surface. Salt water forms the working fluid of living cells. pH and salts regulate the associations of proteins, DNA, cells, and colloids, and the conformations of biopolymers. Nervous systems would not function without ion fluxes. Electrostatic interactions are also important in batteries, corrosion, and electroplating. Charge interactions obey Coulomb’s law. When more than two charged par- ticles interact, the energies are sums of Coulombic interactions. To calculate such sums, we introduce the concepts of the electric field, Gauss’s law, and the electrostatic potential. With these tools, you can determine the electrostatic force exerted by one charged object on another, as when an ion interacts with a protein, DNA molecule, or membrane, or when a charged polymer changes conformation. Coulomb’s law was discovered in careful experiments by H Cavendish (1731–1810), J Priestley (1733–1804), and CA Coulomb (1736–1806) on macro- scopic objects such as magnets, glass rods, charged spheres, and silk cloths. Coulomb’s law applies to a wide range of size scales, including atoms, molecules, and biological cells. It states that the interaction energy u(r ) 385 between two charges in a vacuum is Cq q u(r ) = 1 2 , (20.1) r where q1 and q2 are the magnitudes of the two charges, r is the distance sep- arating them, and C = 1/4πε0 is a proportionality constant (see box below). -
Manual of Style
Manual Of Style 1 MANUAL OF STYLE TABLE OF CONTENTS CHAPTER 1 GENERAL PROVISIONS ...............3 101.0 Scope .............................................. 3 102.0 Codes and Standards..................... 3 103.0 Code Division.................................. 3 104.0 Table of Contents ........................... 4 CHAPTER 2 ADMINISTRATION .........................6 201.0 Administration ................................. 6 202.0 Chapter 2 Definitions ...................... 6 203.0 Referenced Standards Table ......... 6 204.0 Individual Chapter Administrative Text ......................... 6 205.0 Appendices ..................................... 7 206.0 Installation Standards ..................... 7 207.0 Extract Guidelines .......................... 7 208.0 Index ............................................... 9 CHAPTER 3 TECHNICAL STYLE .................... 10 301.0 Technical Style ............................. 10 302.0 Technical Rules ............................ 10 Table 302.3 Possible Unenforceable and Vague Terms ................................ 10 303.0 Health and Safety ........................ 11 304.0 Rules for Mandatory Documents .................................... 11 305.0 Writing Mandatory Requirements ............................... 12 Table 305.0 Typical Mandatory Terms............. 12 CHAPTER 4 EDITORIAL STYLE ..................... 14 401.0 Editorial Style ................................ 14 402.0 Definitions ...................................... 14 403.0 Units of Measure ............................ 15 404.0 Punctuation -
CAR-ANS Part 5 Governing Units of Measurement to Be Used in Air and Ground Operations
CIVIL AVIATION REGULATIONS AIR NAVIGATION SERVICES Part 5 Governing UNITS OF MEASUREMENT TO BE USED IN AIR AND GROUND OPERATIONS CIVIL AVIATION AUTHORITY OF THE PHILIPPINES Old MIA Road, Pasay City1301 Metro Manila UNCOTROLLED COPY INTENTIONALLY LEFT BLANK UNCOTROLLED COPY CAR-ANS PART 5 Republic of the Philippines CIVIL AVIATION REGULATIONS AIR NAVIGATION SERVICES (CAR-ANS) Part 5 UNITS OF MEASUREMENTS TO BE USED IN AIR AND GROUND OPERATIONS 22 APRIL 2016 EFFECTIVITY Part 5 of the Civil Aviation Regulations-Air Navigation Services are issued under the authority of Republic Act 9497 and shall take effect upon approval of the Board of Directors of the CAAP. APPROVED BY: LT GEN WILLIAM K HOTCHKISS III AFP (RET) DATE Director General Civil Aviation Authority of the Philippines Issue 2 15-i 16 May 2016 UNCOTROLLED COPY CAR-ANS PART 5 FOREWORD This Civil Aviation Regulations-Air Navigation Services (CAR-ANS) Part 5 was formulated and issued by the Civil Aviation Authority of the Philippines (CAAP), prescribing the standards and recommended practices for units of measurements to be used in air and ground operations within the territory of the Republic of the Philippines. This Civil Aviation Regulations-Air Navigation Services (CAR-ANS) Part 5 was developed based on the Standards and Recommended Practices prescribed by the International Civil Aviation Organization (ICAO) as contained in Annex 5 which was first adopted by the council on 16 April 1948 pursuant to the provisions of Article 37 of the Convention of International Civil Aviation (Chicago 1944), and consequently became applicable on 1 January 1949. The provisions contained herein are issued by authority of the Director General of the Civil Aviation Authority of the Philippines and will be complied with by all concerned. -
Project Physics Reader 4, Light and Electromagnetism
DOM/KEITRESUME ED 071 897 SE 015 534 TITLE Project Physics Reader 4,Light and Electromagnetism. INSTITUTION Harvard 'Jail's, Cambridge,Mass. Harvard Project Physics. SPONS AGENCY Office of Education (DREW), Washington, D.C. Bureau of Research. BUREAU NO BR-5-1038 PUB DATE 67 CONTRACT 0M-5-107058 NOTE . 254p.; preliminary Version EDRS PRICE MF-$0.65 HC-49.87 DESCRIPTORS Electricity; *Instructional Materials; Li ,t; Magnets;, *Physics; Radiation; *Science Materials; Secondary Grades; *Secondary School Science; *Supplementary Reading Materials IDENTIFIERS Harvard Project Physics ABSTRACT . As a supplement to Project Physics Unit 4, a collection. of articles is presented.. in this reader.for student browsing. The 21 articles are. included under the ,following headings: _Letter from Thomas Jefferson; On the Method of Theoretical Physics; Systems, Feedback, Cybernetics; Velocity of Light; Popular Applications of.Polarized Light; Eye and Camera; The laser--What it is and Doe0; A .Simple Electric Circuit: Ohmss Law; The. Electronic . Revolution; The Invention of the Electric. Light; High Fidelity; The . Future of Current Power Transmission; James Clerk Maxwell, ., Part II; On Ole Induction of Electric Currents; The Relationship of . Electricity and Magnetism; The Electromagnetic Field; Radiation Belts . .Around the Earth; A .Mirror for the Brain; Scientific Imagination; Lenses and Optical Instruments; and "Baffled!." Illustrations for explanation use. are included. The work of Harvard. roject Physics haS ...been financially supported by: the Carnegie Corporation ofNew York, the_ Ford Foundations, the National Science Foundation.the_Alfred P. Sloan Foundation, the. United States Office of Education, and Harvard .University..(CC) Project Physics Reader An Introduction to Physics Light and Electromagnetism U S DEPARTMENT OF HEALTH. -
CAR-ANS PART 05 Issue No. 2 Units of Measurement to Be Used In
CIVIL AVIATION REGULATIONS AIR NAVIGATION SERVICES Part 5 Governing UNITS OF MEASUREMENT TO BE USED IN AIR AND GROUND OPERATIONS CIVIL AVIATION AUTHORITY OF THE PHILIPPINES Old MIA Road, Pasay City1301 Metro Manila INTENTIONALLY LEFT BLANK CAR-ANS PART 5 Republic of the Philippines CIVIL AVIATION REGULATIONS AIR NAVIGATION SERVICES (CAR-ANS) Part 5 UNITS OF MEASUREMENTS TO BE USED IN AIR AND GROUND OPERATIONS 22 APRIL 2016 EFFECTIVITY Part 5 of the Civil Aviation Regulations-Air Navigation Services are issued under the authority of Republic Act 9497 and shall take effect upon approval of the Board of Directors of the CAAP. APPROVED BY: LT GEN WILLIAM K HOTCHKISS III AFP (RET) DATE Director General Civil Aviation Authority of the Philippines Issue 2 15-i 16 May 2016 CAR-ANS PART 5 FOREWORD This Civil Aviation Regulations-Air Navigation Services (CAR-ANS) Part 5 was formulated and issued by the Civil Aviation Authority of the Philippines (CAAP), prescribing the standards and recommended practices for units of measurements to be used in air and ground operations within the territory of the Republic of the Philippines. This Civil Aviation Regulations-Air Navigation Services (CAR-ANS) Part 5 was developed based on the Standards and Recommended Practices prescribed by the International Civil Aviation Organization (ICAO) as contained in Annex 5 which was first adopted by the council on 16 April 1948 pursuant to the provisions of Article 37 of the Convention of International Civil Aviation (Chicago 1944), and consequently became applicable on 1 January 1949. The provisions contained herein are issued by authority of the Director General of the Civil Aviation Authority of the Philippines and will be complied with by all concerned.