Physics 1202: Lecture 4 Today s Agenda. Today s Topic :
|
|
- Lenard Shelton
- 5 years ago
- Views:
Transcription
1 Physics 1202: Lecture 4 Today s Agenda Announcements: Lectures posted on: HW assignments, solutions etc. Homework #1: On Masterphysics: due this coming Friday Go to the syllabus and click on instructions to register (in textbook section). Make sure to input oyur information to google form rthamerica/ Labs: Begin this week Today s Topic : Chapter 20: Electric energy & potential Review of electric potential & Equipotentials Capacitors Effect of dielectrics Energy storage Chapter 21: Electric current & DC-circuits Electric current 1
2 20-Electric Potential V Q 4pe 0 R Q 4pe 0 r C R R R r r B q B r A A path independence equipotentials Electric potential V By analogy with electric field Þ We have Þ Therefore F
3 Point charges For a point charge, the formula is: For N charges Þ simply the algebraic sum of the potential due to each charge separately. q 1 q 2 r 1 x r 2 r 3 q : Equipotentials Defined as: The locus of points with the same potential. Example: for a point charge, the equipotentials are spheres centered on the charge. GENERAL PROPERTY: The Electric Field is always perpendicular to an Equipotential Surface. Why?? Along the surface, there is NO change in V (it s an equipotential!) So, there is NO E component along the surface either E must therefore be normal to surface 3
4 Equipotential Surfaces: examples For two point charges: 2017 Pearson Education, Inc. Conductors Claim The surface of a conductor is always an equipotential surface (in fact, the entire conductor is an equipotential) Why?? If surface were not equipotential, there would be an Electric Field component parallel to the surface and the charges would move!! Note Positive charges move from regions of higher potential to lower potential (move from high potential energy to lower PE). Equilibrium means charges rearrange so potentials equal. 4
5 Charge on Conductors? How is charge distributed on the surface of a conductor? KEY: Must produce E=0 inside the conductor and E normal to the surface q Spherical example (with little off-center charge): E=0 inside conducting shell. - charge density induced on inner surface non-uniform. charge density induced on outer surface uniform E outside has spherical symmetry centered on spherical conducting shell. A Point Charge Near Conducting Plane q V= a 5
6 A Point Charge Near Conducting Plane a q The magnitude of the force is - Image Charge The test charge is attracted to a conducting plane Equipotential Example Field lines more closely spaced near end with most curvature. Field lines ^ to surface near the surface (since surface is equipotential). Equipotentials have similar shape as surface near the surface. Equipotentials will look more circular (spherical) at large r. 6
7 Equipotential & Electric Field An ideal conductor is an equipotential surface 2 conductors at same V, the more curved one has a larger electric field around it Also true for different parts of the same conductor Explains why more charges at edges Applications: human body There are electric fields inside the human body the body is not a perfect conductor, so there are also potential differences. An electrocardiograph plots the heart s electrical activity An electroencephalograph measures the electrical activity of the brain: 7
8 20-5 Definitions & Examples a b L d A Capacitance A capacitor is a device whose purpose is to store electrical energy which can then be released in a controlled manner during a short period of time. Q=CV - A capacitor consists of 2 spatially separated conductors which can be charged to Q and -Q respectively. The capacitance is derived from the capacity to carry a charge Q when a voltage V is applied The capacitance is defined as the ratio of the charge on one conductor of the capacitor to the potential difference between the conductors. DV or V Q
9 Capacitance A capacitance C of the device Q=CV Should not depend on Q nor V! That means should depend on how it is made Material, geometry, dimensions DV or V Q Should be intrinsic to the capacitor. Is this a "good" definition? Does the capacitance belong only to the capacitor, independent of the charge and voltage? Example: Parallel Plate Capacitor Calculate the capacitance. We assume s, - s charge densities on each plate with potential difference V: so Need Q: Need V: recall or where Dx = d 9
10 Recall:Two infinite planes Same charge but opposite Fields of both planes cancel out outside They add up inside Perfect to store energy! Example: Parallel Plate Capacitor Calculate the capacitance: Assume Q,-Q on plates with potential difference V. d A Þ As hoped for, the capacitance of this capacitor depends only on its geometry (A,d). 10
11 Dimensions of capacitance C = Q/V Þ [C] = F(arad) = C/V = [Q/V] A Farad is very large Often will see µf or pf d A Example: Two plates, A = 10cm x 10cm d = 1cm apart Þ C = Ae 0 /d = = 0.01m 2 /0.01m * 8.852e-12 C 2 /Jm = X F = pf Lecture 4 ACT 1 Suppose the capacitor shown here is charged to Q and then the battery disconnected. Now suppose I pull the plates further apart so that the final separation is d 1. d 1 > d d 1 d A A If the initial capacitance is C 0 and the final capacitance is C 1, is A) C 1 > C 0 B) C 1 = C 0 C) C 1 < C 0 11
12 Example : Isolated Sphere Can we define the capacitance of a single isolated sphere? The sphere has the ability to store a certain amount of charge at a given voltage (versus V=0 at infinity) Need DV: V = 0 V R = k e Q/R So, C = R/k e Dielectrics Empirical observation: Inserting a non-conducting material between the plates of a capacitor changes the VALUE of the capacitance. For the same charge Q 0 Lowers the potential difference Increases the capacitance 12
13 Dielectrics A dielectric is an insulating material that, when placed between the plates of a capacitor, increases the capacitance Why? polarization of the material. An Atomic Description of Dielectrics Polarization of the material alignment of small dipoles create a small electric field E pol E pol is in the opposite direction Ratio without/with dielectric The field is smaller: k > 1 13
14 Parallel Plate Example Charge a parallel plate capacitor filled with vacuum (air) to potential difference V 0. An amount of charge Q = C 0 V 0 is deposited on each plate. Now insert material with dielectric constant k. Charge Q remains constant Electric field decreases also: But E and V are related by Voltage decreases from V 0 to So, C = k C 0 Definition: Dielectrics The dielectric constant of a material is the ratio of the capacitance when filled with the dielectric to that without it. i.e. k values are always > 1 (e.g., glass = 5.6; water = 78) They INCREASE the capacitance of a capacitor (generally good, since it is hard to make big capacitors They permit more energy to be stored on a given capacitor than otherwise with vacuum (i.e., air) 14
15 20-5 Capacitors and Dielectrics If the electric field in a dielectric becomes too large it can tear the electrons off the atoms, thereby enabling the material to conduct. This is called dielectric breakdown; the field at which this happens is called the dielectric strength Pearson Education, Inc. Applications of Capacitors Camera Flash The flash attachment on a camera uses a capacitor A battery is used to charge the capacitor The energy stored in the capacitor is released when the button is pushed to take a picture The charge is delivered very quickly, illuminating the subject when more light is needed 15
16 Applications of Capacitors Computers Computers use capacitors in many ways! Some keyboards use capacitors at the bases of the keys! When the key is pressed, the capacitor spacing decreases and the capacitance increases! The key is recognized by the change in capacitance Energy of a Capacitor How much energy is stored in a charged capacitor? Calculate the work provided (usually by a battery) to charge a capacitor to /- Q: Calculate incremental work DW needed to add charge Dq to - capacitor at voltage V: But DW is also the change in potential energy DU The total U to charge to Q is shaded triangle: V In terms of the voltage V: V q V q =q/c q Dq Q 16
17 Lecture 4 ACT 2 The same capacitor as last time. The capacitor is charged to Q and then the battery disconnected. Then I pull the plates further apart so that the final separation is d 1. d 1 > d If the initial energy is U 0 and the final capacitance is U 1, is d d 1 A A A) U 1 > U 0 B) U 1 = U 0 C) U 1 < U 0 Where is the Energy Stored? Claim: energy is stored in the Electric field itself. Think of the energy needed to charge the capacitor as being the energy needed to create the field. To calculate the energy density in the field, first consider the constant field generated by a parallel plate capacitor: The Electric field is given by: Þ The energy density u in the field is given by: Units: J/m 3 17
18 Summary Suppose the capacitor shown here is charged to Q and then the battery disconnected. d A Now suppose I pull the plates further apart so that the final separation is d 1. How do the quantities Q, W, C, V, E change? Q: W: C: V: E: remains the same.. no way for charge to leave. increases.. add energy to system by separating decreases.. since energy, but Q remains same increases.. since C, but Q remains same remains the same.. depends only on chg density How much do these quantities change?.. exercise for student!! answers: 21 e R I e = R I 18
19 Overview Charges in motion mechanical motion electric current How charges move in a conductor Definition of electric current 19
20 Charges in Motion Up to now we have considered fixed charges on isolated bodies motion under simple forces (e.g. a single charge moving in a constant electric field) We have also considered conductors charges are free to move we also said that E=0 inside a conductor If E=0 and there is any friction (resistance) present no charge will move! Charges in motion We know from experience that charges do move inside conductors - this is the definition of a conductor Is there a contradiction? no E V 1 V 2 E Up to now we have considered isolated conductors in equilibrium. Charge has nowhere to go except shift around on the body. Charges shift until they cancel the E field, then come to rest. Now we consider circuits in which charges can circulate if driven by a force such as a battery. 20
21 Analogy with fluids Consider a hose filled with water Need a difference of potential for fluid to flow Same is true for electric charges Current Definition E Consider charges moving down a conductor in which there is an Note: electric This field. definition assumes the current in the direction of If we take a cross section of the wire, over some amount of time Dt we will the count positive a certain particles, number of charges (or total amount of charge) DQ moving by. We define NOT in current the direction as the ratio of of the these electrons! quantities, I avg = DQ / Dt Units for I, Coulombs/Second (C/s) or Amperes (A) 21
22 How charges move in a conducting material E Electric force causes gradual drift of bouncing electrons down the wire in the direction of -E. Drift speed of the electrons is VERY slow compared to the speed of their bouncing motion, roughly 1 m / h! (see example later) Good conductors are those with LOTS of mobile electrons. How charges move in a conducting material E DQ is the number of carriers in some volume times the charge on each carrier (q). Let n be the carrier density, n = # carriers / volume. The relevant volume is A * (v d Dt). Why? So, DQ = n A v d Dt q And I avg = DQ/Dt = n A v d q More on this later v d = Δx/ Δt 22
23 Drift speed in a copper wire The copper wire in a typical residential building has a cross-section area of 3.31e-6 m 2. If it carries a current of 10.0 A, what is the drift speed of the electrons? (Assume that each copper atom contributes one free electron to the current.) The density of copper is 8.95 g/cm 3, its molar mass 63.5 g/mol. Volume of copper (1 mol): Because each copper atom contributes one free electron to the current, we have (n = #carriers/volume) Drift speed in a copper wire, ctd. We find that the drift speed is with charge / electron q Thus 23
24 What makes charges move? Need to create DV recall W = -DU A battery uses chemical reactions to produce a potential difference V 1 V 2 Fluid analogy: person lifting water causing it to flow through the paddle wheel and do work. E Electromotive force Electric potential difference between the terminals of a battery is called the electromotive force or emf: - e Remember despite its name, the emf is an electric potential, not a force. The amount of work it takes to move a charge ΔQ from one terminal to the other is: 24
25 Electric current The direction of current flow from the positive terminal to the negative one was decided before it was realized that electrons are negatively charged. Therefore, current flows around a circuit in the direction a positive charge would move; electrons move the other way. However, this does not matter in most circuits Pearson Education, Inc. Recap of today s lecture Chapter 20: Electric energy & potential Review of electric potential & Equipotentials Capacitors Effect of dielectrics Energy storage Chapter 21: Electric current & DC-circuits Electric current Homework #1 on Mastering Physics From Chapter 19 Due this Friday Labs started this week 25
Physics 1502: Lecture 8 Today s Agenda. Today s Topic :
Physics 1502: Lecture 8 Today s Agenda Announcements: Lectures posted on: www.phys.uconn.edu/~rcote/ HW assignments, solutions etc. Homework #3: On Masterphysics today: due next Friday Go to masteringphysics.com
More informationPhysics 1202: Lecture 3 Today s Agenda
Physics 1202: Lecture 3 Today s Agenda Announcements: Lectures posted on: www.phys.uconn.edu/~rcote/ HW assignments, solutions etc. Homework #1: On Masterphysics: due this coming Friday Go to the syllabus
More informationAgenda for Today. Elements of Physics II. Capacitors Parallel-plate. Charging of capacitors
Capacitors Parallel-plate Physics 132: Lecture e 7 Elements of Physics II Charging of capacitors Agenda for Today Combinations of capacitors Energy stored in a capacitor Dielectrics in capacitors Physics
More informationAgenda for Today. Elements of Physics II. Capacitors Parallel-plate. Charging of capacitors
Capacitors Parallel-plate Physics 132: Lecture e 7 Elements of Physics II Charging of capacitors Agenda for Today Combinations of capacitors Energy stored in a capacitor Dielectrics in capacitors Physics
More informationChapter 19 Electric Potential and Electric Field
Chapter 19 Electric Potential and Electric Field The electrostatic force is a conservative force. Therefore, it is possible to define an electrical potential energy function with this force. Work done
More informationiclicker A metal ball of radius R has a charge q. Charge is changed q -> - 2q. How does it s capacitance changed?
1 iclicker A metal ball of radius R has a charge q. Charge is changed q -> - 2q. How does it s capacitance changed? q A: C->2 C0 B: C-> C0 C: C-> C0/2 D: C->- C0 E: C->-2 C0 2 iclicker A metal ball of
More informationChapter 16. Electric Energy and Capacitance
Chapter 16 Electric Energy and Capacitance Electric Potential Energy The electrostatic force is a conservative force It is possible to define an electrical potential energy function with this force Work
More informationChapter 20 Electric Potential and Electric Potential Energy
Chapter 20 Electric Potential and Electric Potential Energy 1 Overview of Chapter 20 Electric Potential Energy and the Electric Potential! Energy Conservation! The Electric Potential of Point Charges!
More informationW05D1 Conductors and Insulators Capacitance & Capacitors Energy Stored in Capacitors
W05D1 Conductors and Insulators Capacitance & Capacitors Energy Stored in Capacitors W05D1 Reading Assignment Course Notes: Sections 3.3, 4.5, 5.1-5.4 1 Outline Conductors and Insulators Conductors as
More information(3.5.1) V E x, E, (3.5.2)
Lecture 3.5 Capacitors Today we shall continue our discussion of electrostatics and, in particular, the concept of electrostatic potential energy and electric potential. The main example which we have
More informationLecture Outline Chapter 21. Physics, 4 th Edition James S. Walker. Copyright 2010 Pearson Education, Inc.
Lecture Outline Chapter 21 Physics, 4 th Edition James S. Walker Chapter 21 Electric Current and Direct- Current Circuits Units of Chapter 21 Electric Current Resistance and Ohm s Law Energy and Power
More informationPhysics 102: Lecture 04 Capacitors (& batteries)
Physics 102: Lecture 04 Capacitors (& batteries) Physics 102: Lecture 4, Slide 1 I wish the checkpoints were given to us on material that we learned from the previous lecture, rather than on material from
More informationChapter 16. Electric Energy and Capacitance
Chapter 16 Electric Energy and Capacitance Electric Potential of a Point Charge The point of zero electric potential is taken to be at an infinite distance from the charge The potential created by a point
More informationPhysics 1502: Lecture 9 Today s Agenda
Physics 1502: Lecture 9 Today s Agenda Announcements: Lectures posted on: www.phys.uconn.edu/~rcote/ HW assignments, solutions etc. Homework #3: On Masterphysics : due Friday at 8:00 AM Go to masteringphysics.com
More informationCapacitors (Chapter 26)
Capacitance, C Simple capacitive circuits Parallel circuits Series circuits Combinations Electric energy Dielectrics Capacitors (Chapter 26) Capacitors What are they? A capacitor is an electric device
More informationPHY101: Major Concepts in Physics I. Photo: J. M. Schwarz
Welcome back to PHY101: Major Concepts in Physics I Photo: J. M. Schwarz Announcements In class today we will finish Chapter 17 on electric potential energy and electric potential and perhaps begin Chapter
More informationPhysics Electricity & Op-cs Lecture 8 Chapter 24 sec Fall 2017 Semester Professor
Physics 24100 Electricity & Op-cs Lecture 8 Chapter 24 sec. 1-2 Fall 2017 Semester Professor Kol@ck How Much Energy? V 1 V 2 Consider two conductors with electric potentials V 1 and V 2 We can always pick
More informationPotential from a distribution of charges = 1
Lecture 7 Potential from a distribution of charges V = 1 4 0 X Smooth distribution i q i r i V = 1 4 0 X i q i r i = 1 4 0 Z r dv Calculating the electric potential from a group of point charges is usually
More informationChapter 24 Capacitance and Dielectrics
Chapter 24 Capacitance and Dielectrics 1 Capacitors and Capacitance A capacitor is a device that stores electric potential energy and electric charge. The simplest construction of a capacitor is two parallel
More informationSharpen thinking about connections among electric field, electric potential difference, potential energy
PHYS 2015 -- Week 6 Sharpen thinking about connections among electric field, electric potential difference, potential energy Apply the ideas to capacitance and the parallel plate capacitor For exclusive
More informationCapacitors II. Physics 2415 Lecture 9. Michael Fowler, UVa
Capacitors II Physics 2415 Lecture 9 Michael Fowler, UVa Today s Topics First, some review then Storing energy in a capacitor How energy is stored in the electric field Dielectrics: why they strengthen
More informationCapacitance and Dielectrics
Slide 1 / 39 Capacitance and Dielectrics 2011 by Bryan Pflueger Capacitors Slide 2 / 39 A capacitor is any two conductors seperated by an insulator, such as air or another material. Each conductor has
More informationChapter 24 Capacitance and Dielectrics
Chapter 24 Capacitance and Dielectrics Lecture by Dr. Hebin Li Goals for Chapter 24 To understand capacitors and calculate capacitance To analyze networks of capacitors To calculate the energy stored in
More informationSources of Potential (EMF)
Sources of Potential (EMF) A source of potential difference is sometimes called a source of EMF, a widely used term, which stands for ElectroMotive Force. Your author points out that this is an outdated
More informationEnergy Stored in Capacitors
Energy Stored in Capacitors U = 1 2 qv q = CV U = 1 2 CV 2 q 2 or U = 1 2 C 37 Energy Density in Capacitors (1) We define the, u, as the electric potential energy per unit volume Taking the ideal case
More informationElectric Potential Energy Chapter 16
Electric Potential Energy Chapter 16 Electric Energy and Capacitance Sections: 1, 2, 4, 6, 7, 8, 9 The electrostatic force is a conservative force It is possible to define an electrical potential energy
More informationChapter 1 The Electric Force
Chapter 1 The Electric Force 1. Properties of the Electric Charges 1- There are two kinds of the electric charges in the nature, which are positive and negative charges. - The charges of opposite sign
More informationGeneral Physics (PHY 2140)
General Physics (PHY 2140) Lecture 7 Electrostatics and electrodynamics Capacitance and capacitors capacitors with dielectrics Electric current current and drift speed resistance and Ohm s law http://www.physics.wayne.edu/~apetrov/phy2140/
More informationPhysics 115. Energy in E fields Electric Current Batteries Resistance. General Physics II. Session 21
Physics 115 General Physics II Session 21 Energy in E fields Electric Current Batteries Resistance R. J. Wilkes Email: phy115a@u.washington.edu Home page: http://courses.washington.edu/phy115a/ 5/6/14
More informationChapter 21 Electric Current and Direct- Current Circuits
Chapter 21 Electric Current and Direct- Current Circuits 1 Overview of Chapter 21 Electric Current and Resistance Energy and Power in Electric Circuits Resistors in Series and Parallel Kirchhoff s Rules
More informationHomework. Reading: Chap. 29, Chap. 31 and Chap. 32. Suggested exercises: 29.17, 29.19, 29.22, 29.23, 29.24, 29.26, 29.27, 29.29, 29.30, 29.31, 29.
Homework Reading: Chap. 29, Chap. 31 and Chap. 32 Suggested exercises: 29.17, 29.19, 29.22, 29.23, 29.24, 29.26, 29.27, 29.29, 29.30, 29.31, 29.32 Problems: 29.49, 29.51, 29.52, 29.57, 29.58, 29.59, 29.63,
More informationReading: Electrostatics 3. Key concepts: Capacitance, energy storage, dielectrics, energy in the E-field.
Reading: Electrostatics 3. Key concepts: Capacitance, energy storage, dielectrics, energy in the E-field. 1.! Questions about charging and discharging capacitors. When an uncharged capacitor is connected
More informationPhysics 202: Lecture 5, Pg 1
Resistance Resistors Series Parallel Ohm s law Electric Circuits Current Physics 132: Lecture e 15 Elements of Physics II Kirchhoff s laws Agenda for Today Physics 202: Lecture 5, Pg 1 Electric Current
More informationFriday July 11. Reminder Put Microphone On
Friday July 11 8:30 AM 9:0 AM Catch up Lecture 3 Slide 5 Electron projected in electric field problem Chapter 23 Problem 29 Cylindrical shell problem surrounding wire Show Faraday Ice Pail no chrage inside
More information2014 F 2014 AI. 1. Why must electrostatic field at the surface of a charged conductor be normal to the surface at every point? Give reason.
2014 F 1. Why must electrostatic field at the surface of a charged conductor be normal to the surface at every point? Give reason. 2. Figure shows the field lines on a positive charge. Is the work done
More informationUniversity Physics (PHY 2326)
Chapter 23 University Physics (PHY 2326) Lecture 5 Electrostatics Electrical energy potential difference and electric potential potential energy of charged conductors Capacitance and capacitors 3/26/2015
More informationUniversity Physics 227N/232N Old Dominion University
University Physics 227N/232N Old Dominion University (More) Chapter 23, Capacitors Lab deferred to Fri Feb 28 Exam Solutions will be posted Tuesday PM QUIZ this Fri (Feb 21), Fred lectures Mon (Feb 24)
More informationReview. Spring Semester /21/14. Physics for Scientists & Engineers 2 1
Review Spring Semester 2014 Physics for Scientists & Engineers 2 1 Notes! Homework set 13 extended to Tuesday, 4/22! Remember to fill out SIRS form: https://sirsonline.msu.edu Physics for Scientists &
More informationLecture 20. March 22/24 th, Capacitance (Part I) Chapter , Pages
Lecture 0 March /4 th, 005 Capacitance (Part I) Reading: Boylestad s Circuit Analysis, 3 rd Canadian Edition Chapter 10.1-6, Pages 8-94 Assignment: Assignment #10 Due: March 31 st, 005 Preamble: Capacitance
More informationIntermediate Physics PHYS102
Intermediate Physics PHYS102 Dr Richard H. Cyburt Assistant Professor of Physics My office: 402c in the Science Building My phone: (304) 384-6006 My email: rcyburt@concord.edu My webpage: www.concord.edu/rcyburt
More informationChapter 25. Capacitance
Chapter 25 Capacitance 1 1. Capacitors A capacitor is a twoterminal device that stores electric energy. 2 2. Capacitance The figure shows the basic elements of any capacitor two isolated conductors of
More informationAP Physics C. Electricity - Term 3
AP Physics C Electricity - Term 3 Interest Packet Term Introduction: AP Physics has been specifically designed to build on physics knowledge previously acquired for a more in depth understanding of the
More informationChapter 24. Capacitance and Dielectrics Lecture 1. Dr. Armen Kocharian
Chapter 24 Capacitance and Dielectrics Lecture 1 Dr. Armen Kocharian Capacitors Capacitors are devices that store electric charge Examples of where capacitors are used include: radio receivers filters
More informationElectric Potential. Capacitors (Chapters 28, 29)
Electric Potential. Capacitors (Chapters 28, 29) Electric potential energy, U Electric potential energy in a constant field Conservation of energy Electric potential, V Relation to the electric field strength
More informationPhysics 219 Question 1 January
Lecture 6-16 Physics 219 Question 1 January 30. 2012. A (non-ideal) battery of emf 1.5 V and internal resistance 5 Ω is connected to a light bulb of resistance 50 Ω. How much power is delivered to the
More informationExam 1 Solutions. The ratio of forces is 1.0, as can be seen from Coulomb s law or Newton s third law.
Prof. Eugene Dunnam Prof. Paul Avery Feb. 6, 007 Exam 1 Solutions 1. A charge Q 1 and a charge Q = 1000Q 1 are located 5 cm apart. The ratio of the electrostatic force on Q 1 to that on Q is: (1) none
More informationGeneral Physics II. Conducting concentric spheres Two concentric spheres of radii R and r. The potential difference between the spheres is
apacitors and Dielectrics The ideas of energy storage in E-fields can be carried a step further by understanding the concept of "apacitance" onsider a sphere with a total charge, Q, and a radius, R From
More informationChapter 2: Capacitor And Dielectrics
hapter 2: apacitor And Dielectrics In this chapter, we are going to discuss the different ways that a capacitor could be arranged in a circuit and how its capacitance could be increased. Overview apacitor
More informationElectric Field of a uniformly Charged Thin Spherical Shell
Electric Field of a uniformly Charged Thin Spherical Shell The calculation of the field outside the shell is identical to that of a point charge. The electric field inside the shell is zero. What are the
More informationCapacitors and more. Lecture 9. Chapter 29. Physics II. Course website:
Lecture 9 Chapter 29 Physics II Capacitors and more Course website: http://faculty.uml.edu/andriy_danylov/teaching/physicsii Lecture Capture: http://echo360.uml.edu/danylov201415/physics2spring.html The
More informationCapacitors and more. Lecture 9. Chapter 29. Physics II. Course website:
Lecture 9 Chapter 29 Physics II Capacitors and more Course website: http://faculty.uml.edu/andriy_danylov/teaching/physicsii Lecture Capture: http://echo360.uml.edu/danylov201415/physics2spring.html The
More informationCapacitance and capacitors. Dr. Loai Afana
apacitance and capacitors apacitors apacitors are devices that store energy in an electric field. apacitors are used in many every-day applications Heart defibrillators amera flash units apacitors are
More informationChapter 18. Circuit Elements, Independent Voltage Sources, and Capacitors
Chapter 18 Circuit Elements, Independent Voltage Sources, and Capacitors Ideal Wire _ + Ideal Battery Ideal Resistor Ideal Capacitor Series Parallel An ideal battery provides a constant potential difference
More informationToday s agenda: Capacitors and Capacitance. You must be able to apply the equation C=Q/V.
Today s agenda: Capacitors and Capacitance. You must be able to apply the equation C=Q/V. Capacitors: parallel plate, cylindrical, spherical. You must be able to calculate the capacitance of capacitors
More informationCoulomb s Law Pearson Education Inc.
Coulomb s Law Coulomb s Law: The magnitude of the electric force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance
More informationElectric Potential Energy Conservative Force
Electric Potential Energy Conservative Force Conservative force or field is a force field in which the total mechanical energy of an isolated system is conserved. Examples, Gravitation, Electrostatic,
More informationChapter 17. Potential and Capacitance
Chapter 17 Potential and Capacitance Potential Voltage (potential) is the analogue of water pressure while current is the analogue of flow of water in say gal/min or Kg/s Think of a potential as the words
More informationGeneral Physics (PHY 2140)
General Physics (PHY 2140) Lecture 4 Electrostatics and electrodynamics Capacitance and capacitors capacitors with dielectrics Electric current current and drift speed resistance and Ohm s law resistivity
More informationChapter 26. Capacitance and Dielectrics
Chapter 26 Capacitance and Dielectrics Capacitors Capacitors are devices that store electric charge Examples of where capacitors are used include: radio receivers filters in power supplies to eliminate
More informationCapacitance. A different kind of capacitor: Work must be done to charge a capacitor. Capacitors in circuits. Capacitor connected to a battery
Capacitance The ratio C = Q/V is a conductor s self capacitance Units of capacitance: Coulomb/Volt = Farad A capacitor is made of two conductors with equal but opposite charge Capacitance depends on shape
More informationNews. Charge and Potential. Charge Density. Charge and Potential Quiz #2: Monday, 3/14, 10AM Same procedure as for quiz R +
News Charge and Potential Quiz #2: Monday, 3/14, 10AM Same procedure as for quiz 1 Review in class Fri, 3/11 Evening review, Fri, 3/11, 68PM 2 practice quizzes ( practice problems) Formula sheet R Charged
More informationChapter 2: Capacitors And Dielectrics
hapter 2: apacitors And Dielectrics 2.1 apacitance and capacitors in series and parallel L.O 2.1.1 Define capacitance and use capacitance apacitor is a device that is capable of storing electric charges
More informationClass 6. Capacitance and Capacitors. Physics 106. Winter Press CTRL-L to view as a slide show. Class 6. Physics 106.
and in and Energy Winter 2018 Press CTRL-L to view as a slide show. From last time: The field lines are related to the field as follows: What is the electric potential? How are the electric field and the
More informationChapter 29. Electric Potential: Charged Conductor
hapter 29 Electric Potential: harged onductor 1 Electric Potential: harged onductor onsider two points (A and B) on the surface of the charged conductor E is always perpendicular to the displacement ds
More informationAP Physics C. Magnetism - Term 4
AP Physics C Magnetism - Term 4 Interest Packet Term Introduction: AP Physics has been specifically designed to build on physics knowledge previously acquired for a more in depth understanding of the world
More informationCapacitance and Dielectrics
Chapter 24 Capacitance and Dielectrics PowerPoint Lectures for University Physics, Thirteenth Edition Hugh D. Young and Roger A. Freedman Lectures by Wayne Anderson Goals for Chapter 24 To understand capacitors
More informationLouisiana State University Physics 2102, Exam 2, March 5th, 2009.
PRINT Your Name: Instructor: Louisiana State University Physics 2102, Exam 2, March 5th, 2009. Please be sure to PRINT your name and class instructor above. The test consists of 4 questions (multiple choice),
More informationPhysics 42 Exam 2 PRACTICE Name: Lab
Physics 42 Exam 2 PRACTICE Name: Lab 1 2 3 4 Conceptual Multiple Choice (2 points each) Circle the best answer. 1.Rank in order, from brightest to dimmest, the identical bulbs A to D. A. C = D > B > A
More informationPhysics 1202: Lecture 7 Today s Agenda. Today s Topic :
Physics 1202: Today s Agenda Announcements: Lectures posted on: www.phys.uconn.edu/~rcote/ Office hours: Monday 2:30-3:30 Thursday 3:00-4:00 Homework #2: due this coming Friday/ Labs: Already begun last
More informationHollow Conductors. A point charge +Q is placed at the center of the conductors. The induced charges are: 1. Q(I1) = Q(I2) = -Q; Q(O1) = Q(O2)= +Q
O2 I2 O1 I1 Hollow Conductors A point charge +Q is placed at the center of the conductors. The induced charges are: 1. Q(I1) = Q(I2) = -Q; Q(O1) = Q(O2)= +Q 2. Q(I1) = Q(I2) = +Q; Q(O1) = Q(O2)= -Q 3.
More informationGeneral Physics - E&M (PHY 1308) - Lecture Notes. General Physics - E&M (PHY 1308) Lecture Notes
General Physics - E&M (PHY 1308) Lecture Notes Lecture 009: Using Capacitors SteveSekula, 15 February 2011 (created 14 February 2011) Discuss the energy stored in a capacitor Discuss how to use capacitors
More informationA) I B) II C) III D) IV E) V
1. A square loop of wire moves with a constant speed v from a field-free region into a region of uniform B field, as shown. Which of the five graphs correctly shows the induced current i in the loop as
More informationChapter 16. Current and Drift Speed. Electric Current, cont. Current and Drift Speed, cont. Current and Drift Speed, final
Chapter 6 Current, esistance, and Direct Current Circuits Electric Current Whenever electric charges of like signs move, an electric current is said to exist The current is the rate at which the charge
More informationPhysics 212. Lecture 7. Conductors and Capacitance. Physics 212 Lecture 7, Slide 1
Physics 212 Lecture 7 Conductors and Capacitance Physics 212 Lecture 7, Slide 1 Conductors The Main Points Charges free to move E = 0 in a conductor Surface = Equipotential In fact, the entire conductor
More informationENGR 2405 Chapter 6. Capacitors And Inductors
ENGR 2405 Chapter 6 Capacitors And Inductors Overview This chapter will introduce two new linear circuit elements: The capacitor The inductor Unlike resistors, these elements do not dissipate energy They
More informationSection 1: Electric Fields
PHY 132 Outline of Lecture Notes i Section 1: Electric Fields A property called charge is part of the basic nature of protons and electrons. Large scale objects become charged by gaining or losing electrons.
More informationCapacitance and Dielectrics. Chapter 26 HW: P: 10,18,21,29,33,48, 51,53,54,68
Capacitance and Dielectrics Chapter 26 HW: P: 10,18,21,29,33,48, 51,53,54,68 Capacitors Capacitors are devices that store electric charge and energy Examples of where capacitors are used include: radio
More informationMansfield Independent School District AP Physics C: Electricity and Magnetism Year at a Glance
Mansfield Independent School District AP Physics C: Electricity and Magnetism Year at a Glance First Six-Weeks Second Six-Weeks Third Six-Weeks Lab safety Lab practices and ethical practices Math and Calculus
More informationPhysics for Scientists and Engineers 4th Edition 2017
A Correlation and Narrative Summary of Physics for Scientists and Engineers 4th Edition 2017 To the AP Physics C: Electricity and Magnetism Course Description AP is a trademark registered and/or owned
More informationUniversity Physics (PHY 2326)
Chapter 25 University Physics (PHY 2326) Lecture 7 Electrostatics and electrodynamics Capacitance and capacitors capacitors with dielectrics Electric current current and drift speed resistance and Ohm
More informationCapacitor: any two conductors, one with charge +Q, other with charge -Q Potential DIFFERENCE between conductors = V
Physics 2102 Gabriela González Capacitor: any two conductors, one with charge +Q, other with charge -Q Potential DIFFERENCE between conductors = V Units of capacitance: Farad (F) = Coulomb/Volt -Q +Q Uses:
More informationChapter 21. And. Electric Potential due to Point Charges. Capacitors
Chapter 21 Electric Potential due to Point Charges And Capacitors Potential Difference, commonly called Voltage Recall: E = F/q o = force per unit charge (units: N/C) V = W/q o = work per unit charge
More informationCoulomb s constant k = 9x10 9 N m 2 /C 2
1 Part 2: Electric Potential 2.1: Potential (Voltage) & Potential Energy q 2 Potential Energy of Point Charges Symbol U mks units [Joules = J] q 1 r Two point charges share an electric potential energy
More informationChapter 24 Capacitance and Dielectrics
Chapter 24 Capacitance and Dielectrics 1 Capacitors and Capacitance A capacitor is a device that stores electric potential energy and electric charge. The simplest construction of a capacitor is two parallel
More informationCapacitors And Dielectrics
1 In this small e-book we ll learn about capacitors and dielectrics in short and then we ll have some questions discussed along with their solutions. I ll also give you a practices test series which you
More informationPHY102 Electricity Course Summary
TOPIC 1 ELECTOSTTICS PHY1 Electricity Course Summary Coulomb s Law The magnitude of the force between two point charges is directly proportional to the product of the charges and inversely proportional
More informationWELCOME TO PERIOD 14. Homework Exercise #13 is due today. Watch video 3 Edison s Miracle of Light for class discussion next Tuesday or Wednesday.
WELCOME TO PERIOD 14 Homework Exercise #13 is due today. Watch video 3 Edison s Miracle of Light for class discussion next Tuesday or Wednesday. PHYSICS 1103 PERIOD 14 What is an electric circuit? How
More informationPHYSICS - CLUTCH CH 24: CAPACITORS & DIELECTRICS.
!! www.clutchprep.com CONCEPT: CAPACITORS AND CAPACITANCE A CAPACITOR is formed by two surfaces of equal/opposite charge brought close together - Separation of charge potential energy stored Connecting
More informationAC vs. DC Circuits. Constant voltage circuits. The voltage from an outlet is alternating voltage
Circuits AC vs. DC Circuits Constant voltage circuits Typically referred to as direct current or DC Computers, logic circuits, and battery operated devices are examples of DC circuits The voltage from
More informationChapter 24: Capacitance and dielectrics
Chapter 24: Capacitance and dielectrics Capacitor: a device store electric energy How to define capacitance In parallel and/or in series Electric energy stored in a capacitor Dielectric materials Capacitor:
More informationAnnouncements. Homework: Test 1: Practice Exams posted on WebCT Review Sessions by discussion TFs
Homework: Announcements Webassign HW due on SUNDAY at 11:59pm No Hand-in Homework Test 1: Feb 17 th, 6-7:30 pm Location: SMG 105 Chapters: 21-24 Practice Exams posted on WebCT Review Sessions by discussion
More informationChapter 30: Potential and Field. (aka Chapter 29 The Sequel )
Chapter 30: Potential and Field (aka Chapter 29 The Sequel ) Electric Field and Electric Potential: Two Sides of the Same Coin A set of charges ( source charges ) alters the space around them. This alteration
More informationPhysics 2220 Fall 2010 George Williams SECOND MIDTERM - REVIEW PROBLEMS
Physics 0 Fall 010 George Williams SECOND MIDTERM - REVIEW PROBLEMS The last four problems are from last years second midterm. Solutions are available on the class web site.. There are no solutions for,
More informationPhysics 1402: Lecture 12 Today s Agenda
Physics 1402: Lecture 12 Today s Agenda Announcements: Lectures posted on: www.phys.uconn.edu/~rcote/ HW assignments, solutions etc. Homework #4: On Masterphysics : due next Friday at 8:00 AM Go to masteringphysics.com
More informationPhysics (
Exercises Question 2: Two charges 5 0 8 C and 3 0 8 C are located 6 cm apart At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero
More information1. zero. Where an electric field line crosses an equipotential surface, the angle between the field line and the equipotential is
Week 5 Where an electric field line crosses an equipotential surface, the angle between the field line and the equipotential is 1. zero 2. between zero and 90 3. 90 4. not enough information given to
More informationAP Physics C - E & M
AP Physics C - E & M Current and Circuits 2017-07-12 www.njctl.org Electric Current Resistance and Resistivity Electromotive Force (EMF) Energy and Power Resistors in Series and in Parallel Kirchoff's
More informationPhysics 169. Luis anchordoqui. Kitt Peak National Observatory. Thursday, February 22, 18
Physics 169 Kitt Peak National Observatory Luis anchordoqui 1 4.1 Capacitors A capacitor is a system of two conductors that carries equal and opposite charges A capacitor stores charge and energy in the
More informationPH2200 Practice Exam II Summer 2003
PH00 Practice Exam II Summer 00 INSTRUCTIONS. Write your name and student identification number on the answer sheet and mark your recitation section.. Please cover your answer sheet at all times.. This
More informationElectricity. Revision Notes. R.D.Pilkington
Electricity Revision Notes R.D.Pilkington DIRECT CURRENTS Introduction Current: Rate of charge flow, I = dq/dt Units: amps Potential and potential difference: work done to move unit +ve charge from point
More information