18.1 Electric Charge and Static Electricity Electricity Video
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Printer Tech Tips—Cause & Effects of Static Electricity in Paper
Printer Tech Tips Cause & Effects of Static Electricity in Paper Problem The paper has developed a static electrical charge causing an abnormal sheet-to- sheet or sheet-to-material attraction which is difficult to separate. This condition may result in feeder trip-offs, print voids from surface contamination, ink offset, Sappi Printer Technical Service or poor sheet jog in the delivery. 877 SappiHelp (727 7443) Description Static electricity is defined as a non-moving, non-flowing electrical charge or in simple terms, electricity at rest. Static electricity becomes visible and dynamic during the brief moment it sparks a discharge and for that instant it’s no longer at rest. Lightning is the result of static discharge as is the shock you receive just before contacting a grounded object during unusually dry weather. Matter is composed of atoms, which in turn are composed of protons, neutrons, and electrons. The number of protons and neutrons, which make up the atoms nucleus, determine the type of material. Electrons orbit the nucleus and balance the electrical charge of the protons. When both negative and positive are equal, the charge of the balanced atom is neutral. If electrons are removed or added to this configuration, the overall charge becomes either negative or positive resulting in an unbalanced atom. Materials with high conductivity, such as steel, are called conductors and maintain neutrality because their electrons can move freely from atom to atom to balance any applied charges. Therefore, conductors can dissipate static when properly grounded. Non-conductive materials, or insulators such as plastic and wood, have the opposite property as their electrons can not move freely to maintain balance. -
The Lorentz Force
CLASSICAL CONCEPT REVIEW 14 The Lorentz Force We can find empirically that a particle with mass m and electric charge q in an elec- tric field E experiences a force FE given by FE = q E LF-1 It is apparent from Equation LF-1 that, if q is a positive charge (e.g., a proton), FE is parallel to, that is, in the direction of E and if q is a negative charge (e.g., an electron), FE is antiparallel to, that is, opposite to the direction of E (see Figure LF-1). A posi- tive charge moving parallel to E or a negative charge moving antiparallel to E is, in the absence of other forces of significance, accelerated according to Newton’s second law: q F q E m a a E LF-2 E = = 1 = m Equation LF-2 is, of course, not relativistically correct. The relativistically correct force is given by d g mu u2 -3 2 du u2 -3 2 FE = q E = = m 1 - = m 1 - a LF-3 dt c2 > dt c2 > 1 2 a b a b 3 Classically, for example, suppose a proton initially moving at v0 = 10 m s enters a region of uniform electric field of magnitude E = 500 V m antiparallel to the direction of E (see Figure LF-2a). How far does it travel before coming (instanta> - neously) to rest? From Equation LF-2 the acceleration slowing the proton> is q 1.60 * 10-19 C 500 V m a = - E = - = -4.79 * 1010 m s2 m 1.67 * 10-27 kg 1 2 1 > 2 E > The distance Dx traveled by the proton until it comes to rest with vf 0 is given by FE • –q +q • FE 2 2 3 2 vf - v0 0 - 10 m s Dx = = 2a 2 4.79 1010 m s2 - 1* > 2 1 > 2 Dx 1.04 10-5 m 1.04 10-3 cm Ϸ 0.01 mm = * = * LF-1 A positively charged particle in an electric field experiences a If the same proton is injected into the field perpendicular to E (or at some angle force in the direction of the field. -
Capacitance and Dielectrics Capacitance
Capacitance and Dielectrics Capacitance General Definition: C === q /V Special case for parallel plates: εεε A C === 0 d Potential Energy • I must do work to charge up a capacitor. • This energy is stored in the form of electric potential energy. Q2 • We showed that this is U === 2C • Then we saw that this energy is stored in the electric field, with a volume energy density 1 2 u === 2 εεε0 E Potential difference and Electric field Since potential difference is work per unit charge, b ∆∆∆V === Edx ∫∫∫a For the parallel-plate capacitor E is uniform, so V === Ed Also for parallel-plate case Gauss’s Law gives Q Q εεε0 A E === σσσ /εεε0 === === Vd so C === === εεε0 A V d Spherical example A spherical capacitor has inner radius a = 3mm, outer radius b = 6mm. The charge on the inner sphere is q = 2 C. What is the potential difference? kq From Gauss’s Law or the Shell E === Theorem, the field inside is r 2 From definition of b kq 1 1 V === dr === kq −−− potential difference 2 ∫∫∫a r a b 1 1 1 1 === 9 ×××109 ××× 2 ×××10−−−9 −−− === 18 ×××103 −−− === 3 ×××103 V −−−3 −−−3 3 ×××10 6 ×××10 3 6 What is the capacitance? C === Q /V === 2( C) /(3000V ) === 7.6 ×××10−−−4 F A capacitor has capacitance C = 6 µF and charge Q = 2 nC. If the charge is Q.25-1 increased to 4 nC what will be the new capacitance? (1) 3 µF (2) 6 µF (3) 12 µF (4) 24 µF Q. -
On the Nature of Electric Charge
Vol. 9(4), pp. 54-60, 28 February, 2014 DOI: 10.5897/IJPS2013.4091 ISSN 1992 - 1950 International Journal of Physical Copyright © 2014 Author(s) retain the copyright of this article Sciences http://www.academicjournals.org/IJPS Full Length Research Paper On the nature of electric charge Jafari Najafi, Mahdi 1730 N Lynn ST apt A35, Arlington, VA 22209 USA. Received 10 December, 2013; Accepted 14 February, 2014 A few hundred years have passed since the discovery of electricity and electromagnetic fields, formulating them as Maxwell's equations, but the nature of an electric charge remains unknown. Why do particles with the same charge repel and opposing charges attract? Is the electric charge a primary intrinsic property of a particle? These questions cannot be answered until the nature of the electric charge is identified. The present study provides an explicit description of the gravitational constant G and the origin of electric charge will be inferred using generalized dimensional analysis. Key words: Electric charge, gravitational constant, dimensional analysis, particle mass change. INTRODUCTION The universe is composed of three basic elements; parameters. This approach is of great generality and mass-energy (M), length (L), and time (T). Intrinsic mathematical simplicity that simply and directly properties are assigned to particles, including mass, postulates a hypothesis for the nature of the electric electric charge, and spin, and their effects are applied in charge. Although the final formula is a guesswork based the form of physical formulas that explicitly address on dimensional analysis of electric charges, it shows the physical phenomena. The meaning of some particle existence of consistency between the final formula and properties remains opaque. -
Modeling Optical Metamaterials with Strong Spatial Dispersion
Fakultät für Physik Institut für theoretische Festkörperphysik Modeling Optical Metamaterials with Strong Spatial Dispersion M. Sc. Karim Mnasri von der KIT-Fakultät für Physik des Karlsruher Instituts für Technologie (KIT) genehmigte Dissertation zur Erlangung des akademischen Grades eines DOKTORS DER NATURWISSENSCHAFTEN (Dr. rer. nat.) Tag der mündlichen Prüfung: 29. November 2019 Referent: Prof. Dr. Carsten Rockstuhl (Institut für theoretische Festkörperphysik) Korreferent: Prof. Dr. Michael Plum (Institut für Analysis) KIT – Die Forschungsuniversität in der Helmholtz-Gemeinschaft Erklärung zur Selbstständigkeit Ich versichere, dass ich diese Arbeit selbstständig verfasst habe und keine anderen als die angegebenen Quellen und Hilfsmittel benutzt habe, die wörtlich oder inhaltlich über- nommenen Stellen als solche kenntlich gemacht und die Satzung des KIT zur Sicherung guter wissenschaftlicher Praxis in der gültigen Fassung vom 24. Mai 2018 beachtet habe. Karlsruhe, den 21. Oktober 2019, Karim Mnasri Als Prüfungsexemplar genehmigt von Karlsruhe, den 28. Oktober 2019, Prof. Dr. Carsten Rockstuhl iv To Ouiem and Adam Thesis abstract Optical metamaterials are artificial media made from subwavelength inclusions with un- conventional properties at optical frequencies. While a response to the magnetic field of light in natural material is absent, metamaterials prompt to lift this limitation and to exhibit a response to both electric and magnetic fields at optical frequencies. Due tothe interplay of both the actual shape of the inclusions and the material from which they are made, but also from the specific details of their arrangement, the response canbe driven to one or multiple resonances within a desired frequency band. With such a high number of degrees of freedom, tedious trial-and-error simulations and costly experimen- tal essays are inefficient when considering optical metamaterials in the design of specific applications. -
Electromagnetism
Electromagnetism Electric Charge Two types: positive and negative Like charges repel, opposites attract Forces come in a matched pair Each charge pushes or pulls on the other Forces have equal magnitudes and opposite directions Forces increase with decreasing separation Charge is quantized Charge is an intrinsic property of matter Electrons are negatively charged (-1.6 x 10-19 coulomb’s each) Protons are positively charged (+1.6 x 10-19 coulomb’s each) Net charge is the sum of an object’s charges Most objects have zero net charge (neutral – equal numbers of + and -) Electric Fields Charges push on each other through empty space Charge one creates an “electric field” This electric field pushes on charge two An electric field is a structure in space that pushes on electric charge The magnitude of the field is proportional to the magnitude of the force on a test charge The direction of the field is the direction of the force on a positive test charge Magnetic Poles Two Types: north and south Like poles repel, opposites attract Forces come in matched pairs Forces increase with decreasing separation Analogous to electric charges EXCEPT: No isolated magnetic poles have ever been found! Net pole on an object is always zero! Most atoms are magnetic, but most materials are not Atomic magnetism is perfectly cancelled Material is indifferent to nearby magnetic poles Some materials do not have full cancellation Ferromagnetic materials respond to magnetic poles Magnetic Fields A magnetic field is a structure in space that pushes on magnetic poles -
Teaching H. C. Ørsted's Scientific Work in Danish High School Physics
UNIVERSITY OF COPENHAGEN FACULTY OF SCIENCE Ida Marie Monberg Hindsholm Teaching H. C. Ørsted's Scientific Work in Danish High School Physics Masterʹs thesis Department of Science Education 19 July 2018 Master's thesis Teaching H. C. Ørsted’s Scientific Work in Danish High School Physics Submitted 19 July 2018 Author Ida Marie Monberg Hindsholm, B.Sc. E-mail [email protected] Departments Niels Bohr Institute, University of Copenhagen Department of Science Education, University of Copenhagen Main supervisor Ricardo Avelar Sotomaior Karam, Associate Professor, Department of Science Education, University of Copenhagen Co-supervisor Steen Harle Hansen, Associate Professor, Niels Bohr Institute, University of Copenhagen 1 Contents 1 Introduction . 1 2 The Material: H. C. Ørsted's Work . 3 2.1 The Life of Hans Christian Ørsted . 3 2.2 Ørsted’s Metaphysical Framework: The Dynamical Sys- tem............................. 6 2.3 Ritter and the failure in Paris . 9 2.4 Ørsted’s work with acoustic and electric figures . 12 2.5 The discovery of electromagnetism . 16 2.6 What I Use for the Teaching Sequence . 19 3 Didactic Theory . 20 3.1 Constructivist teaching . 20 3.2 Inquiry Teaching . 22 3.3 HIPST . 24 4 The Purpose and Design of the Teaching Sequence . 27 4.1 Factual details and lesson plan . 28 5 Analysis of Transcripts and Writings . 40 5.1 Method of Analysis . 40 5.2 Practical Problems . 41 5.3 Reading Original Ørsted's Texts . 42 5.4 Inquiry and Experiments . 43 5.5 "Role play" - Thinking like Ørsted . 48 5.6 The Reflection Corner . 51 5.7 Evaluation: The Learning Objectives . -
F = BIL (F=Force, B=Magnetic Field, I=Current, L=Length of Conductor)
Magnetism Joanna Radov Vocab: -Armature- is the power producing part of a motor -Domain- is a region in which the magnetic field of atoms are grouped together and aligned -Electric Motor- converts electrical energy into mechanical energy -Electromagnet- is a type of magnet whose magnetic field is produced by an electric current -First Right-Hand Rule (delete) -Fixed Magnet- is an object made from a magnetic material and creates a persistent magnetic field -Galvanometer- type of ammeter- detects and measures electric current -Magnetic Field- is a field of force produced by moving electric charges, by electric fields that vary in time, and by the 'intrinsic' magnetic field of elementary particles associated with the spin of the particle. -Magnetic Flux- is a measure of the amount of magnetic B field passing through a given surface -Polarized- when a magnet is permanently charged -Second Hand-Right Rule- (delete) -Solenoid- is a coil wound into a tightly packed helix -Third Right-Hand Rule- (delete) Major Points: -Similar magnetic poles repel each other, whereas opposite poles attract each other -Magnets exert a force on current-carrying wires -An electric charge produces an electric field in the region of space around the charge and that this field exerts a force on other electric charges placed in the field -The source of a magnetic field is moving charge, and the effect of a magnetic field is to exert a force on other moving charge placed in the field -The magnetic field is a vector quantity -We denote the magnetic field by the symbol B and represent it graphically by field lines -These lines are drawn ⊥ to their entry and exit points -They travel from N to S -If a stationary test charge is placed in a magnetic field, then the charge experiences no force. -
Materials That Cause Static Electricity
Materials that Cause Static Electricity http://www.school-for-champions.com/science/static_materials.htm Some materials cause or create more static electricity than others. Since static electricity is the collection of electrically charged particles on the surface of a material, various materials have a tendency of either giving up electrons and becoming positive (+) in charge or attracting electrons and becoming negative (−) in charge. The Triboelectric Series is a list of materials, showing which have a greater tendency to become positive (+) and which have a greater tendency to become negative (−). The list is a handy tool to determine which combinations of materials create the most static electricity. Questions you may have include: What are materials in the Triboelectric Series? What are the best combinations of materials? What are acceptable combinations? Triboelectric Series Common materials are listed according how well they create static electricity when rubbed with another material, as well as what charge the material will possess. Become positive in charge The following materials will tend to give up electrons when brought in contact with other materials. They are listed from those with the greatest tendency to give electrons to those that barely give up electrons. Materials that gain a positive (+) electrical charge (or tend to give up electrons) Greatest tendency to giving up electrons and becoming highly positive (+) in Dry human skin charge Leather Rabbit fur Fur is often used to create static electricity Glass The glass on your TV screen gets charged and collects dust Human hair "Flyaway hair" is a good example of having a moderate positive (+) charge Nylon Wool Lead A surprise that lead would collect as much static electricity as cat fur Cat fur Silk Aluminum Gives up some electrons Paper Neutral There are very few materials that do not tend to readily attract or give up electrons when brought in contact or rubbed with other materials. -
Chapter 5 Capacitance and Dielectrics
Chapter 5 Capacitance and Dielectrics 5.1 Introduction...........................................................................................................5-3 5.2 Calculation of Capacitance ...................................................................................5-4 Example 5.1: Parallel-Plate Capacitor ....................................................................5-4 Interactive Simulation 5.1: Parallel-Plate Capacitor ...........................................5-6 Example 5.2: Cylindrical Capacitor........................................................................5-6 Example 5.3: Spherical Capacitor...........................................................................5-8 5.3 Capacitors in Electric Circuits ..............................................................................5-9 5.3.1 Parallel Connection......................................................................................5-10 5.3.2 Series Connection ........................................................................................5-11 Example 5.4: Equivalent Capacitance ..................................................................5-12 5.4 Storing Energy in a Capacitor.............................................................................5-13 5.4.1 Energy Density of the Electric Field............................................................5-14 Interactive Simulation 5.2: Charge Placed between Capacitor Plates..............5-14 Example 5.5: Electric Energy Density of Dry Air................................................5-15 -
Electric Potential
Electric Potential • Electric Potential energy: b U F dl elec elec a • Electric Potential: b V E dl a Field is the (negative of) the Gradient of Potential dU dV F E x dx x dx dU dV F UF E VE y dy y dy dU dV F E z dz z dz In what direction can you move relative to an electric field so that the electric potential does not change? 1)parallel to the electric field 2)perpendicular to the electric field 3)Some other direction. 4)The answer depends on the symmetry of the situation. Electric field of single point charge kq E = rˆ r2 Electric potential of single point charge b V E dl a kq Er ˆ r 2 b kq V rˆ dl 2 a r Electric potential of single point charge b V E dl a kq Er ˆ r 2 b kq V rˆ dl 2 a r kq kq VVV ba rrba kq V const. r 0 by convention Potential for Multiple Charges EEEE1 2 3 b V E dl a b b b E dl E dl E dl 1 2 3 a a a VVVV 1 2 3 Charges Q and q (Q ≠ q), separated by a distance d, produce a potential VP = 0 at point P. This means that 1) no force is acting on a test charge placed at point P. 2) Q and q must have the same sign. 3) the electric field must be zero at point P. 4) the net work in bringing Q to distance d from q is zero. -
Electric Charge
Electric Charge • Electric charge is a fundamental property of atomic particles – such as electrons and protons • Two types of charge: negative and positive – Electron is negative, proton is positive • Usually object has equal amounts of each type of charge so no net charge • Object is said to be electrically neutral Charged Object • Object has a net charge if two types of charge are not in balance • Object is said to be charged • Net charge is always small compared to the total amount of positive and negative charge contained in an object • The net charge of an isolated system remains constant Law of Electric Charges • Charged objects interact by exerting forces on one another • Law of Charges: Like charges repel, and opposite charges attract • The standard unit (SI) of charge is the Coulomb (C) Electric Properties • Electrical properties of materials such as metals, water, plastic, glass and the human body are due to the structure and electrical nature of atoms • Atoms consist of protons (+), electrons (-), and neutrons (electrically neutral) Atom Schematic view of an atom • Electrically neutral atoms contain equal numbers of protons and electrons Conductors and Insulators • Atoms combine to form solids • Sometimes outermost electrons move about the solid leaving positive ions • These mobile electrons are called conduction electrons • Solids where electrons move freely about are called conductors – metal, body, water • Solids where charge can’t move freely are called insulators – glass, plastic Charging Objects • Only the conduction