Chapter 27 Current and Resistance 27.1 Electric Current


 Alan Cooper
 4 years ago
 Views:
Transcription
1 Chapter 27 Current and esistance 27.1 Electric Current Electric current: dq dt, unit: ampere 1A = 1C s The rate at which charge flows through a surface. No longer have static equilibrium. E and Q can 0 inside a conductor! The direction of the current is defined as the direction of the flow of positive charge, which is opposite the direction of flow of electrons. Microscopic View of Electric Current Within a time t, the number of charge canflow through a surface is: Volume charge density = A(v d t) n v d : the drift speed (average speed) of charge carriers. n: the density of charge carriers (Carriers move in a zigzag fashion due to collision with atoms.) Total charge: Q = A(v d t) n q q: the charge on each charge carrier. Q Thus, = lim t0 t = nqv d A Example: Drift Speed in a Copper Wire A copper wire of crosssectional area m 2, carries a current of 10A. The density of copper is 8.95 g/cm 3, and atomic mass is 63.5 g/mol. Find v d Solution: v d = nqa Need to find n =? charge/ m 3 1 m 3 copper weights 1 m g/cm 3 = g t contains g/63.5 (g/mol) = mol of copper. t contains ( mol)( ) = atoms Assume each copper atom contributes one free electron. Then: n = electrons/ m 3 v d = nqa = 10C / s ( m 3 )( C)( m 2 ) = m/s = mm/s t is slow! For electron to drift 1 meter long copper wire: 1000 mm/ (mm/s) = 4065 s = 67 minutes Q: Why a light turn on so fast when a switch is thrown?
2 27.2 esistance and Ohm s Law Define current density : current per unit area J / A = nqv d (A/m 2 ) The current density is proportional to the electric field: J = E, Where, is called the conductivity of the conductor. Also: = 1/ is the esistivity of a conductor Ohm s Law: many materials follows: J = E, and is a constant. Ohmic: Materials obey Ohm s law, such as most metals. Nonohmic: Materials do not obey Ohm s law Since J = E and V =EL, V = EL = J L L = ( JA) A = L A = V = = L A is called resistance of a conductor Unit for : ohm (), 1 1V 1A Unit for : ( m) Material esistivity Temperature Coefficient ( m) [( C) 1 ] Silver Gold Copper Carbon Silicon Glass ~ Example: A copper wire, 10 m long, A= m 2. (a) Calculate the resistance: = L A = (1.7 10m 108 m) m 2 =1.7 (b) f a potential difference of 1 V is maintained across the wire, what is the current in the wire? = V = 1V = 0.59A = 590mA A Classical Model for electrical conduction Electrons are treated as molecules of gas. When E = 0, average speed of electron = 0. When E 0, the electrons move with a drift velocity v d. Acceleration of the electron: a = qe m Between collisions, the speed of electron:
3 v = v0 + at = v0 + qe m t Take an average: v d = qe m Where, is the average time interval between collisions. = 0 [1+(T T 0 )] 0 is the resistivity at the reference temperature T 0 (usually 20 C). is the tempereature coefficient of resistivity. (Unit 1/ C). Current density: J = nqv d = nq 2 E = E m Therefore, = nq2 m, and = 1 = m nq 2 However, calculated v d is about 10x slower than the true value, and predicted (T) is also not correct. The correct description can only be given using quantum mechanics esistance and Temperature metal T silicon T > 0 < 0 Since, similarly: = 0 [1+ (T T 0 )] Example: Nichrome wire has = / C, it is initially at 20 C. Calculate the temperature at which its resistance is doubled. Solution: Since > 0, increases with temperature, Let = 2 0, then 2 0 = 0 [1+ (T T 0 )] (T T 0 ) = 1 = 1 3 C = 2500 C T = 2500 C + T 0 = 2500 C + 20 C = 2520 C esistivity can be approximated by:
4 27.5 Superconductors A class of material whose resistance goes to zero below a certain temperature, T c. (critical tempereature). () Hg 4.2 T(K) (b) Steady currents can persist in a superconducting loop for years without any applied voltage. (b) Applications: superconducting magnets,.. (b) Current active research: hightemperature superconductors 27.6 Electrical Energy and Power (c) When a charge Q moves through a resistor with potential difference of V, the electrical potential energy decreases by VQ. (d) f the charge is in vacuum, VQ will be converted to the kinetic energy. (quiz 2 problem) (e) n a resistor, VQ become thermal energy, not kinetic energy, due to collision of electrons with atoms. This energy heats up the resistor. The rate at which the charge Q loses potential energy: U = VQ = V t t The power P dissipated in a resistor: P = V Unit: watt. 1W = 1V1A + _ Using, V =, P can also be written as: p = V = 2 = V 2
5 Example: A potential difference of 110 V is applied to a Nichromewire electric heater of = 8. (a)find the current. = V = 110V 8 = 13.8A (b) Find the power rating of the heater. + _ P = 2 = (13.8 A) 2 (8 )= 1.52 kw Example: A lightbulb is rated at 120V/75W. (a) Find the current in the bulb = P V = 75W 120V = 0.625A (b) The resistance of the bulb Ohm s law, = V = 120V = 192 Example: Calculate the cost to burn a 100W lightbulb for 24 h if electricity costs 8 cents per kilowatt hour (kwh). Energy consumed = (0.1 kw)(24 h) = 2.4 kwh Cost = (2.4 kwh)($ 0.08 / kwh) = $ 0.19 Example: A charge of 100,000 C flows through a 60W lightbulb. f the price of electricity is 8 /kwh, what is the cost? Energy consumed = W = qv =110 5 C 120V = J = (kwh)/ = 3.3 kwh Cost = 3.3 kwh 8 /kwh = 26.4
Current and Resistance
Current and Resistance 1 Define the current. Understand the microscopic description of current. Discuss the rat at which the power transfer to a device in an electric current. 2 21 Electric current 22
More informationChapter 17. Current and Resistance. Sections: 1, 3, 4, 6, 7, 9
Chapter 17 Current and Resistance Sections: 1, 3, 4, 6, 7, 9 Equations: 2 2 1 e r q q F = k 2 e o r Q k q F E = = I R V = A L R ρ = )] ( 1 [ o o T T + = α ρ ρ V I V t Q P = = R V R I P 2 2 ) ( = = C Q
More informationElectric Current. Chapter 17. Electric Current, cont QUICK QUIZ Current and Resistance. Sections: 1, 3, 4, 6, 7, 9
Electric Current Chapter 17 Current and Resistance Sections: 1, 3, 4, 6, 7, 9 Whenever electric charges of like signs move, an electric current is said to exist The current is the rate at which the charge
More informationElectric Currents & Resistance
Electric Currents & Resistance Electric Battery A battery produces electricity by transforming chemical energy into electrical energy. The simplest battery contains two plates or rods made of dissimilar
More informationChapter 27. Current and Resistance
Chapter 27 Current and Resistance Electric Current Most practical applications of electricity deal with electric currents. The electric charges move through some region of space. The resistor is a new
More informationChapter 27. Current And Resistance
Chapter 27 Current And Resistance Electric Current Electric current is the rate of flow of charge through some region of space The SI unit of current is the ampere (A) 1 A = 1 C / s The symbol for electric
More informationChapter 25: Electric Current
Chapter 25: Electric Current Conductors and Charge Carriers Consider a conducting piece of metal: The valence electrons are weakly bound to the nuclei form a fluidlike sea of electrons that can move through
More informationNote 5: Current and Resistance
Note 5: Current and Resistance In conductors, a large number of conduction electrons carry electricity. If current flows, electrostatics does not apply anymore (it is a dynamic phenomenon) and there can
More informationChapter 17. Current and Resistance
Chapter 17 Current and Resistance Electric Current The current is the rate at which the charge flows through a surface Look at the charges flowing perpendicularly through a surface of area A I av The SI
More informationElectric Currents and Simple Circuits
1 Electric Currents and Simple Circuits Electrons can flow along inside a metal wire if there is an Efield present to push them along ( F= qe). The flow of electrons in a wire is similar to the flow
More informationChapter 25 Electric Currents and. Copyright 2009 Pearson Education, Inc.
Chapter 25 Electric Currents and Resistance 251 The Electric Battery Volta discovered that electricity could be created if dissimilar metals were connected by a conductive solution called an electrolyte.
More informationChapter 27. Current and Resistance
Chapter 27 Current and Resistance CHAPTER OUTLINE 27.1 Electric Current 27.2 Resistance 27.3 A Model for Electrical Conduction 27.4 Resistance and Temperature 27.5 Superconductors 27.6 Electrical Power
More informationChapter 17 Current and Resistance
Chapter 17 Current and Resistance Current Practical applications were based on static electricity. A steady source of electric current allowed scientists to learn how to control the flow of electric charges
More informationChapter 24: Electric Current
Chapter 24: Electric Current Current Definition of current A current is any motion of charge from one region to another. Suppose a group of charges move perpendicular to surface of area A. The current
More informationChapter 25 Electric Currents and Resistance. Copyright 2009 Pearson Education, Inc.
Chapter 25 Electric Currents and Resistance 254 Resistivity Example 255: Speaker wires. Suppose you want to connect your stereo to remote speakers. (a) If each wire must be 20 m long, what diameter copper
More informationChapter 27: Current & Resistance. HW For Chapter 27: 6, 18, 20, 30, 42, 48, 52, 56, 58, 62, 68
Chapter 27: Current & Resistance HW For Chapter 27: 6, 18, 20, 30, 42, 48, 52, 56, 58, 62, 68 Positive Charges move from HI to LOW potential. HI V LOW V Negative Charges move from LOW to HI potential.
More informationphysics for you February 11 Page 68
urrent Electricity Passage 1 4. f the resistance of a 1 m length of a given wire t is observed that good conductors of heat are also is 8.13 10 3 W, and it carried a current 1, the good conductors of electricity.
More informationChapter 27. Current And Resistance
Chapter 27 Current And Resistance Electric Current Electric current is the rate of flow of charge through some region of space The SI unit of current is the ampere (A) 1 A = 1 C / s The symbol for electric
More informationPhysics 142 Steady Currents Page 1. Steady Currents
Physics 142 Steady Currents Page 1 Steady Currents If at first you don t succeed, try, try again. Then quit. No sense being a damn fool about it. W.C. Fields Electric current: the slow average drift of
More information9/22/16 ANNOUNCEMENT ANNOUNCEMENT FINAL EXAM
ANNOUNCEMENT Exam 1: Tuesday September 27, 2016, 8 PM 10 PM Location: Elliot Hall of Music Covers all readings, lectures, homework from Chapters 21 through 23 Multiple choice (1518 questions) Practice
More informationCurrent and Resistance
Chapter 26 Current and Resistance Copyright 261 Electric Current As Fig. (a) reminds us, any isolated conducting loop regardless of whether it has an excess charge is all at the same potential. No electric
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 informationChapter 25 Current Resistance, and Electromotive Force
Chapter 25 Current Resistance, and Electromotive Force 1 Current In previous chapters we investigated the properties of charges at rest. In this chapter we want to investigate the properties of charges
More information10/14/2018. Current. Current. QuickCheck 30.3
Current If QCurrent is the total amount of charge that has moved past a point in a wire, we define the current I in the wire to be the rate of charge flow: The SI unit for current is the coulomb per second,
More informationChapter 24: Electric Current
Chapter 24: Electric Current Electric current Electric current is a net flow of electric charge. Quantitatively, current is the rate at which charge crosses a given area. I = dq dt dq = q(n AL)=q(n Av
More informationCurrent and Resistance
chapter 27 Current and Resistance 27.1 Electric Current 27.2 Resistance 27.3 A Model for Electrical Conduction 27.4 Resistance and Temperature 27.5 Superconductors 27.6 Electrical Power We now consider
More informationChapter 26 Current and Resistance
Chapter 26 Current and Resistance Electric Current Although an electric current is a stream of moving charges, not all moving charges constitute an electric current. If there is to be an electric current
More informationElectric Current. Electric current is the rate of flow of charge through some region of space The SI unit of current is the ampere (A)
Electric Current Electric current is the rate of flow of charge through some region of space The SI unit of current is the ampere (A) 1 A = 1 C / s The symbol for electric current is I Average Electric
More informationELECTRIC CURRENT INTRODUCTION. Introduction. Electric current
Chapter 7 ELECTRIC CURRENT Introduction Electric current Charge conservation Electric conductivity Microscopic picture Electric power Electromotive force Kirchhoff s rules Summary INTRODUCTION The first
More informationWhat is an Electric Current?
Electric Circuits NTODUCTON: Electrical circuits are part of everyday human life. e.g. Electric toasters, electric kettle, electric stoves All electrical devices need electric current to operate. n this
More informationPhysics 11b Lecture #8
Physics 11b Lecture #8 Current and Resistance S&J Chapter 27 Administravia First midterm this Thursday Covers up to and including capacitance Lectures #1 #7, textbook chapters 23 26 Five problems Problem
More informationClosed loop of moving charges (electrons move  flow of negative charges; positive ions move  flow of positive charges. Nucleus not moving)
Unit 2: Electricity and Magnetism Lesson 3: Simple Circuits Electric circuits transfer energy. Electrical energy is converted into light, heat, sound, mechanical work, etc. The byproduct of any circuit
More informationChapter 25 Electric Currents and Resistance. Copyright 2009 Pearson Education, Inc.
Chapter 25 Electric Currents and Resistance Units of Chapter 25 The Electric Battery Electric Current Ohm s Law: Resistance and Resistors Resistivity Electric Power Units of Chapter 25 Power in Household
More informationChapter 3: Electric Current and DirectCurrent Circuit
Chapter 3: Electric Current and DirectCurrent Circuit n this chapter, we are going to discuss both the microscopic aspect and macroscopic aspect of electric current. Directcurrent is current that flows
More informationNama :.. Kelas/No Absen :
Nama :.. Kelas/No Absen : TASK 2 : CURRENT AND RESISTANCE 1. A car battery is rated at 80 A h. An amperehour is a unit of: A. power B. energy C. current D. charge E. force 2. Current has units: A. kilowatthour
More informationChapter 27 Current and resistance
27.1 Electric Current Chapter 27 Current and resistance 27.2 Resistance 27.3 A Model for Electrical Conduction 27.4 Resistance and Temperature 27.6 Electrical Power 2 27.1 Electric Current Consider a system
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 informationChapter 27. Current and Resistance
Chapter 27 Current and Resistance Electric Current Most practical applications of electricity deal with electric currents. The electric charges move through some region of space. The resistor is a new
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 informationLecture 6 Current and Resistance Ch. 26
Lecture 6 Current and esistance Ch. 6 Cartoon nvention of the battery and Voltaic Cell Warmup problem Topics What is current? Current density Conservation of Current esistance Temperature dependence
More informationPHYSICS. Chapter 27 Lecture FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E RANDALL D. KNIGHT
PHYSICS FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E Chapter 27 Lecture RANDALL D. KNIGHT Chapter 27 Current and Resistance IN THIS CHAPTER, you will learn how and why charge moves through a wire
More information3 Electric current, resistance, energy and power
3 3.1 Introduction Having looked at static charges, we will now look at moving charges in the form of electric current. We will examine how current passes through conductors and the nature of resistance
More informationChapter 21 Electric Current and Direct Current Circuits
Chapter 21 Electric Current and Direct Current Circuits Units of Chapter 21 Electric Current Resistance and Ohm s Law Energy and Power in Electric Circuits Resistors in Series and Parallel Kirchhoff s
More informationChapter 25 Current, Resistance, and Electromotive Force
Chapter 25 Current, Resistance, and Electromotive Force Lecture by Dr. Hebin Li Goals for Chapter 25 To understand current and how charges move in a conductor To understand resistivity and conductivity
More informationGeneral Physics (PHY 2140)
General Physics (PHY 2140) Lecture 9 Electrodynamics Electric current temperature variation of resistance electrical energy and power http://www.physics.wayne.edu/~apetrov/phy2140/ Chapter 1718 1 Department
More informationCurrent and Resistance
Chapter 17 Current and esistance Quick Quizzes 1. (d. Negative charges moving in one direction are equivalent to positive charges moving in the opposite direction. Thus, Ia, Ib, Ic, and Id are equivalent
More informationOhms Law. V = IR V = voltage in volts (aka potential difference) I = Current in amps R = resistance in ohms (Ω)
Ohms Law V = IR V = voltage in volts (aka potential difference) I = Current in amps R = resistance in ohms (Ω) Current How would you define it? Current the movement of electric charge through a medium
More informationChapters 24/25: Current, Circuits & Ohm s law Thursday September 29 th **Register your iclickers**
Chapters 24/25: Current, Circuits & Ohm s law Thursday September 29 th **Register your iclickers** Conductors under dynamic conditions Current, current density, drift velocity Ohm s law Types of conductor
More informationChapter 20 Electric Circuits
Chapter 0 Electric Circuits Chevy olt  Electric vehicle of the future Goals for Chapter 9 To understand the concept of current. To study resistance and Ohm s Law. To observe examples of electromotive
More informationChapter 27 Solutions. )( m 3 = = s = 3.64 h
Chapter 27 Solutions 27.1 I Q t N Q e Q I t (30.0 10 6 A)(40.0 s) 1.20 10 3 C 1.20 10 3 C 1.60 10 19 C/electron 7.50 1015 electrons *27.2 The atomic weight of silver 107.9, and the volume V is V (area)(thickness)
More informationElectric Current. You must know the definition of current, and be able to use it in solving problems.
Today s agenda: Electric Current. You must know the definition of current, and be able to use it in solving problems. Current Density. You must understand the difference between current and current density,
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 informationFlow Rate is the NET amount of water passing through a surface per unit time
Electric Current An Analogy Water Flow in a Pipe H 2 0 gallons/minute Flow Rate is the NET amount of water passing through a surface per unit time Individual molecules are bouncing around with speeds of
More informationDEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS
DEL PHYSCS THE BADDEST CLASS ON CAMPUS B PHYSCS TSOKOS LESSON 54: ELECTRC CURRENT AND ELECTRC RESSTANCE Reading Activity Questions? Objectives By the end of this class you should be able to: Q State the
More informationELECTRICITY UNIT REVIEW
ELECTRICITY UNIT REVIEW S1304: How does the Atomic Model help to explain static electricity? 1. Which best describes static electricity? a) charges that can be collected and held in one place b) charges
More informationChapter 3: Current and Resistance. Direct Current Circuits
Chapter 3: Current and Resistance. Direct Current Circuits 3.1. Electric Current 3.2. Resistance and Resistivity 3.3. Ohm s Law and a Microscopic View of Ohm s Law 3.4. Semiconductors and Superconductors
More informationChapter 27: Current and Resistance
Chapter 7: Current and esistance In this section of the course we will be studying the flow of electric charge, current, in a circuit. We have already seen electric current when we first discussed electric
More information1 Written and composed by: Prof. Muhammad Ali Malik (M. Phil. Physics), Govt. Degree College, Naushera
CURRENT ELECTRICITY Q # 1. What do you know about electric current? Ans. Electric Current The amount of electric charge that flows through a cross section of a conductor per unit time is known as electric
More informationElectric Currents. Resistors (Chapters 2728)
Electric Currents. Resistors (Chapters 2728) Electric current I Resistance R and resistors Relation between current and resistance: Ohm s Law Resistivity ρ Energy dissipated by current. Electric power
More informationInsulators Nonmetals are very good insulators; their electrons are very tightly bonded and cannot move.
SESSION 11: ELECTRIC CIRCUITS Key Concepts Resistance and Ohm s laws Ohmic and nonohmic conductors Series and parallel connection Energy in an electric circuit Xplanation 1. CONDUCTORS AND INSULATORS
More informationPhysics Lecture 19: FRI 10 OCT
Resistance Is Futile! Physics 2113 Jonathan Dowling Physics 2113 Lecture 19: FRI 10 OCT Current & Resistance III Georg Simon Ohm (17891854) Resistance is NOT Futile! Electrons are not completely free
More informationCurrent. I = ei e = en e Av d. The current, which is Coulomb s per second, is simply
Current The current, which is Coulomb s per second, is simply I = ei e = en e Av d e is the charge is the electron! ne is the density of electrons! A is the cross sectional area of the wire! vd is the
More informationPhysics 202, Lecture 8. Exam 1
Physics 202, Lecture 8 Today s Topics More on Exam 1: logistics and minireview Current And Resistance (Ch. 27) Current: Macroscopic and Microscopic Resistance: Macroscopic and Microscopic Electrical Power
More informationChapter 20: Electric Current, Resistance & Ohm s Law. Brent Royuk Phys112 Concordia University
Chapter 20: Electric Current, Resistance & Ohm s Law Brent Royuk Phys112 Concordia University The Minds of Our Own Challenge Light a bulb with a battery and a wire. Could you do it? 2 Introduction Batteries
More informationPHYS 1444 Section 003. Lecture #12
Chapter 5 Power PHYS 1444 Section 003 Alternating Current Microscopic Current Chapter 6 EMF and Terminal Voltage Lecture #1 Tuesday October 9, 01 Dr. Andrew Brandt Resistors in Series and Parallel Energy
More informationChapter 17 Electric Current and Resistance Pearson Education, Inc.c
Chapter 17 Electric Current and Resistance 2010 Pearson Education, Inc.c 1 Units of Chapter 17 Batteries and Direct Current Current and Drift Velocity Resistance and Ohm s Law Electric Power 2010 Pearson
More informationChapter 3: Electric Current And DirectCurrent Circuits
Chapter 3: Electric Current And DirectCurrent Circuits 3.1 Electric Conduction 3.1.1 Describe the microscopic model of current Mechanism of Electric Conduction in Metals Before applying electric field
More informationAP Physics C  E & M
Slide 1 / 27 Slide 2 / 27 AP Physics C  E & M Current, Resistance & Electromotive Force 20151205 www.njctl.org Slide 3 / 27 Electric Current Electric Current is defined as the movement of charge from
More informationand in a simple circuit Part 2
Current, Resistance, and Voltage in a simple circuit Part 2 Electric Current Whenever electric charges of like signs move, an electric current is said to exist. Look at the charges flowing perpendicularly
More informationFrom last time. Today: More on electric potential and connection to Efield How to calculate Efield from V Capacitors and Capacitance
From last time More on electric potential and connection to Efield How to calculate Efield from V Capacitors and Capacitance Today: More on Capacitors and Capacitance Energy stored in Capacitors Current
More informationCurrent. source charges. test charg. 1. Charges in motion
Current 1. Charges in motion 1. Cause of motion 2. Where is it going? 3. Let's keep this going. 2. Current 1. Flow of particles in pipes. 2. A constant problem 3. Conservation Laws 4. Microscopic motion
More informationChapter 21. Current and Direct Current Circuits 21.1 Electric Current
Chapter 21 Current and Direct Current Circuits 21.1 Electric Current Electric Current 1 is defmed as the rate ofcharge flowing through a crosssection. =dq dt ..1 The "81" unit ofelectric current
More informationChapter 20: Electric Current, Resistance & Ohm s Law
Chapter 0: Electric Current, Resistance & Brent Royuk Phys11 Concordia University The Minds of Our Own Challenge Light a bulb with a battery and a wire. Could you do it? Introduction Batteries supply
More informationSection 1 Electric Charge and Force
CHAPTER OUTLINE Section 1 Electric Charge and Force Key Idea questions > What are the different kinds of electric charge? > How do materials become charged when rubbed together? > What force is responsible
More informationElectric Currents and Resistance II
Electric Currents and Resistance II Physics 2415 Lecture 11 Michael Fowler, UVa Today s Topics First we ll mention capacitors Power usage: kwh, etc. The microscopic picture Temperature dependence of resistivity
More information10 N acts on a charge in an electric field of strength 250 N.C What is the value of the charge?
Year 11 Physics Electrical Energy in the Home Name: 1. Draw the electric field lines around a) a single positive charge b) between two opposite charged bodies c) two parallel plates + + + + + + +   
More informationDirect Currents. We will now start to consider charges that are moving through a circuit, currents. Sunday, February 16, 2014
Direct Currents We will now start to consider charges that are moving through a circuit, currents. 1 Direct Current Current usually consists of mobile electrons traveling in conducting materials Direct
More information670 Intro Physics Notes: Electric Current and Circuits
Name: Electric Current Date: / / 670 Intro Physics Notes: Electric Current and Circuits 1. Previously, we learned about static electricity. Static electricity deals with charges that are at rest. 2. Now
More informationELECTRIC CURRENT. Ions CHAPTER Electrons. ELECTRIC CURRENT and DIRECTCURRENT CIRCUITS
LCTRC CURRNT CHAPTR 25 LCTRC CURRNT and DRCTCURRNT CRCUTS Current as the motion of charges The Ampère Resistance and Ohm s Law Ohmic and nonohmic materials lectrical energy and power ons lectrons nside
More informationMonday July 14. Capacitance demo slide 19 Capacitors in series and parallel slide 33 Elmo example
Monday July 14 Lecture 5 Capacitance demo slide 19 Capacitors in series and parallel slide 33 Elmo example Lecture 6 Currents and esistance Lecture 9 Circuits Wear Microphone 1 3 Lecture 6 Current and
More informationAnnouncements. final exam average (excluding regrades): 79% regrade requests are due by Thursday, Sept 28 in recitation
Announcements final exam average (excluding regrades): 79% ill file. regrade requests are due by Thursday, Sept 28 in recitation On a separate sheet of paper, explain the reason for your request. This
More informationElectric currents (primarily, in metals)
Electric currents (primarily, in metals) Benjamin Franklin was experimenting electricity in the mid XVIII Century. Nobody knew if it was the positive charges or negative charges carrying the current through
More informationConducting surface  equipotential. Potential varies across the conducting surface. Lecture 9: Electrical Resistance.
Lecture 9: Electrical Resistance Electrostatics (timeindependent E, I = 0) Stationary Currents (timeindependent E and I 0) E inside = 0 Conducting surface  equipotential E inside 0 Potential varies
More informationResistivity and Temperature Coefficients (at 20 C)
Homework # 4 Resistivity and Temperature Coefficients (at 0 C) Substance Resistivity, Temperature ( m) Coefficient, (C )  Conductors Silver.59 x 00.006 Copper.6 x 00.006 Aluminum.65 x 00.0049 Tungsten
More informationHandout 5: Current and resistance. Electric current and current density
1 Handout 5: Current and resistance Electric current and current density Figure 1 shows a flow of positive charge. Electric current is caused by the flow of electric charge and is defined to be equal to
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 informationElectromagnetism Checklist
Electromagnetism Checklist Elementary Charge and Conservation of Charge 4.1.1A Convert from elementary charge to charge in coulombs What is the charge in coulombs on an object with an elementary charge
More informationphysics 4/7/2016 Chapter 31 Lecture Chapter 31 Fundamentals of Circuits Chapter 31 Preview a strategic approach THIRD EDITION
Chapter 31 Lecture physics FOR SCIENTISTS AND ENGINEERS a strategic approach THIRD EDITION randall d. knight Chapter 31 Fundamentals of Circuits Chapter Goal: To understand the fundamental physical principles
More informationElectrical Circuits. Sources of Voltage
Electrical Circuits ALESSANDRO VOLTA (17451827) ANDRE MARIE AMPERE (17751836) GEORG SIMON OHM (17891854) POTENTIAL IN VOLTS, CURRENT IN AMPS, RESISTANCE IN OHMS! Sources of Voltage Voltage, also known
More informationAP Physics C  E & M
AP Physics C  E & M Current and Circuits 20170712 www.njctl.org Electric Current Resistance and Resistivity Electromotive Force (EMF) Energy and Power Resistors in Series and in Parallel Kirchoff's
More informationCircuitsOhm's Law. 1. Which graph best represents the relationship between the electrical power and the current in a resistor that obeys Ohm s Law?
1. Which graph best represents the relationship between the electrical power and the current in a resistor that obeys Ohm s Law? 2. A potential drop of 50 volts is measured across a 250 ohm resistor.
More informationweek 6 chapter 31 Current and Resistance
week 6 chapter 31 Current and Resistance Which is the correct way to light the lightbulb with the battery? 4) all are correct 5) none are correct 1) 2) 3) Which is the correct way to light the lightbulb
More informationChapter 26 & 27. Electric Current and Direct Current Circuits
Chapter 26 & 27 Electric Current and Direct Current Circuits Electric Current and Direct Current Circuits Current and Motion of Charges Resistance and Ohm s Law Energy in Electric Circuits Combination
More informationStatic Electricity. Electric Field. the net accumulation of electric charges on an object
Static Electricity the net accumulation of electric charges on an object Electric Field force exerted by an e  on anything that has an electric charge opposite charges attract like charges repel Static
More informationElectric current is a flow of electrons in a conductor. The SI unit of electric current is ampere.
C h a p t e r at G l a n c e 4. Electric Current : Electric current is a flow of electrons in a conductor. The SI unit of electric current is ampere. Current = Charge time i.e, I = Q t The SI unit of charge
More informationIntroduction to Electrical Theory and DC Circuits
Introduction to Electrical Theory and DC Circuits For Engineers of All Disciplines by James Doane, PhD, PE Contents 1.0 Course Overview... 4 2.0 Fundamental Concepts... 4 2.1 Electric Charges... 4 2.1.1
More informationPhysics 1302W.400 Lecture 21 Introductory Physics for Scientists and Engineering II
Physics 1302W.400 Lecture 21 Introductory Physics for Scientists and Engineering II In today s lecture, we will learn to: Calculate the resistance of a conductor depending on the material and shape Apply
More informationChapter 18. Direct Current Circuits
Chapter 18 Direct Current Circuits Sources of emf The source that maintains the current in a closed circuit is called a source of emf Any devices that increase the potential energy of charges circulating
More informationCollege Physics B  PHY2054C
Power College  PHY2054C and 09/15/2014 My Office Hours: Tuesday 10:00 AM  Noon 206 Keen Building PHY2054C Power First MiniExam this week on Wednesday!! Location: UPL 101, 10:1011:00 AM Exam on chapters
More information6 Chapter. Current and Resistance
6 Chapter Current and Resistance 6.1 Electric Current... 62 6.1.1 Current Density... 62 6.2 Ohm s Law... 65 6.3 Summary... 68 6.4 Solved Problems... 69 6.4.1 Resistivity of a Cable... 69 6.4.2 Charge
More information