Copyright 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley.

Size: px
Start display at page:

Download "Copyright 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley."

Transcription

1 Lights, sound systems, microwave ovens, and computers are all connected by wires to a battery or an electrical outlet. How and why does electric current flow through a wire? Chapter Goal: To learn how and why charge moves through a conductor as what we call a current.

2 What quantity is represented by the symbol J? A. Resistivity B. Conductivity C. Current density D. Complex impedance E. Johnston s constant

3 What quantity is represented by the symbol J? A. Resistivity B. Conductivity C. Current density D. Complex impedance E. Johnston s constant

4 The electron drift speed in a typical current-carrying wire is A. extremely slow ( 10 4 m/s). B. moderate ( 1 m/s). C. very fast ( 10 4 m/s). D. Could be any of A, B, or C. E. No numerical values were provided.

5 The electron drift speed in a typical current-carrying wire is A. extremely slow ( 10 4 m/s). B. moderate ( 1 m/s). C. very fast ( 10 4 m/s). D. Could be any of A, B, or C. E. No numerical values were provided.

6 All other things being equal, current will be larger in a wire that has a larger value of A. conductivity. B. resistivity. C. the coefficient of current. D. net charge. E. potential.

7 All other things being equal, current will be larger in a wire that has a larger value of A. conductivity. B. resistivity. C. the coefficient of current. D. net charge. E. potential.

8 Conduction electrons behave rather like a fluid forced through a sand pile driven by an electric field rather than pressure. Electrons at a given temperature collide with atoms losing energy gained from the field as heat and drift along the field direction.

9 A naïve model assumes motion with drag proportional to speed Velocity approaches a terminal velocity or drift velocity The terminal velocity is approached exponentially

10 For number density n c [particles/m 3 ] moving with mean velocity v d, each carrying charge e, the electric current density [Coulomb-m -2 -s -1 ] vector is The current di [Coulomb/s = ampere] through area da is The current through a finite open surface is

11 Suppose two nearly perfect conductors are immersed in a less than perfect conducting medium. The current density and electric field are proportional. Ohm s Law applies to electrons in condensed matter and to ion drift in fluids. Electron drift in gases is more complex.

12 Note: resistivity is temperature dependent and ranges over 24 orders of magnitude

13 The electric field and current density in a wire of constant cross section is generally approximated as constant and directed along the wire. Small static charges appear on the surface to enforce this. The total current through a transverse cross section is simply

14 When the electric field and current density in a piece of material of length L and area A are constant, or with the resistance [Ohms] A metal wire is a great conductor/terrible resistor. Carbon is a lousy conductors and decent resistor.

15 Circuit model: neglect voltage drops and resistance in wires. Physical layout Schematic layout 15

16 Electric charge (electrons) are conserved. In a circuit, with negligible wire capacitance, wires have no net charge. Charge cannot build up at any point so must flow smoothly and therefore the current into a point equals the current out.

17 For a junction, the law of conservation of current requires that where the Σ symbol means summation. This basic conservation statement that the sum of the currents into a junction equals the sum of the currents leaving is called Kirchhoff s junction law.

18 QUESTION:

19

20 1 A = 1 C/s is a macroscopic amount of charge!

21 QUESTION: The mean time can be inferred from the conductivity in the context of the classical model. Calculating it from first principles is another matter.

22

23 QUESTION: Calculate the resistance then use V=IR=> I=V/R.

24

25

26 These four wires are made of the same metal. Rank in order, from largest to smallest, the electron currents i a to i d. A. i d > i a > i b > i c B. i b = i d > i a = i c C. i c > i b > i a > i d D. i c > i a = i b > i d E. i b = i c > i a = i d

27 These four wires are made of the same metal. Rank in order, from largest to smallest, the electron currents i a to i d. A. i d > i a > i b > i c B. i b = i d > i a = i c C. i c > i b > i a > i d D. i c > i a = i b > i d E. i b = i c > i a = i d

28 Why does the light in a room come on instantly when you flip a switch several meters away? A. Electrons travel at the speed of light through the wire. B. Because the wire between the switch and the bulb is already full of electrons, a flow of electrons from the switch into the wire immediately causes electrons to flow from the other end of the wire into the lightbulb. C. The switch sends a radio signal which is received by a receiver in the light which tells it to turn on. D. Optical fibers connect the switch with the light, so the signal travels from switch to the light at the speed of light in an optical fiber.

29 Why does the light in a room come on instantly when you flip a switch several meters away? A. Electrons travel at the speed of light through the wire. B. Because the wire between the switch and the bulb is already full of electrons, a flow of electrons from the switch into the wire immediately causes electrons to flow from the other end of the wire into the lightbulb. C. The switch sends a radio signal which is received by a receiver in the light which tells it to turn on. D. Optical fibers connect the switch with the light, so the signal travels from switch to the light at the speed of light in an optical fiber. Actually none of the above

30 What are the magnitude and the direction of the current in the fifth wire? A. 15 A into the junction B. 15 A out of the junction C. 1 A into the junction D. 1 A out of the junction E. Not enough data to determine

31 What are the magnitude and the direction of the current in the fifth wire? A. 15 A into the junction B. 15 A out of the junction C. 1 A into the junction D. 1 A out of the junction E. Not enough data to determine

Homework. Reading: Chap. 30 and Chap. 31

Homework. Reading: Chap. 30 and Chap. 31 Homework Reading: Chap. 30 and Chap. 31 Suggested exercises: 30.1, 30.3, 30.5, 30.6, 30.8, 30.10, 30.12, 30.14, 30.16, 30.18, 30.20, 30.24, 30.26, 30.32, 30.37 Problems: 30.40, 30.43, 30.45, 30.47, 30.49,

More information

week 6 chapter 31 Current and Resistance

week 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 information

10/14/2018. Current. Current. QuickCheck 30.3

10/14/2018. 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 information

Electric currents (primarily, in metals)

Electric 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 information

PHYSICS. Chapter 27 Lecture FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E RANDALL D. KNIGHT

PHYSICS. 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 information

LABORATORY 4 ELECTRIC CIRCUITS I. Objectives

LABORATORY 4 ELECTRIC CIRCUITS I. Objectives LABORATORY 4 ELECTRIC CIRCUITS I Objectives to be able to discuss potential difference and current in a circuit in terms of electric field, work per unit charge and motion of charges to understand that

More information

Electric Charge and Electric field

Electric Charge and Electric field Electric Charge and Electric field ConcepTest 16.1a Electric Charge I Two charged balls are repelling each other as they hang from the ceiling. What can you say about their charges? 1) one is positive,

More information

Current. Lecture 10. Chapter Physics II. Course website:

Current. Lecture 10. Chapter Physics II. Course website: Lecture 10 Chapter 30 Physics II Current Course website: http://faculty.uml.edu/andriy_danylov/teaching/physicsii 95.144 Lecture Capture: http://echo360.uml.edu/danylov201415/physics2spring.html A Model

More information

Physics 202: Lecture 5, Pg 1

Physics 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 information

Introduction to Electricity

Introduction to Electricity Introduction to Electricity Principles of Engineering 2012 Project Lead The Way, Inc. Electricity Movement of electrons Invisible force that provides light, heat, sound, motion... Electricity at the Atomic

More information

physics 4/7/2016 Chapter 31 Lecture Chapter 31 Fundamentals of Circuits Chapter 31 Preview a strategic approach THIRD EDITION

physics 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 information

Electric Currents and Circuits

Electric Currents and Circuits Nicholas J. Giordano www.cengage.com/physics/giordano Chapter 19 Electric Currents and Circuits Marilyn Akins, PhD Broome Community College Electric Circuits The motion of charges leads to the idea of

More information

Parallel Resistors (32.6)

Parallel Resistors (32.6) Parallel Resistors (32.6) Resistors connected at both ends are called parallel resistors The important thing to note is that: the two left ends of the resistors are at the same potential. Also, the two

More information

Parallel Resistors (32.6)

Parallel Resistors (32.6) Parallel Resistors (32.6) Resistors connected at both ends are called parallel resistors Neil Alberding (SFU Physics) Physics 121: Optics, Electricity & Magnetism Spring 2010 1 / 1 Parallel Resistors (32.6)

More information

Chapter 20 Electric Circuits

Chapter 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 information

Agenda for Today. Elements of Physics II. Resistance Resistors Series Parallel Ohm s law Electric Circuits. Current Kirchoff s laws

Agenda for Today. Elements of Physics II. Resistance Resistors Series Parallel Ohm s law Electric Circuits. Current Kirchoff s laws Resistance Resistors Series Parallel Ohm s law Electric Circuits Physics 132: Lecture e 17 Elements of Physics II Current Kirchoff s laws Agenda for Today Physics 201: Lecture 1, Pg 1 Clicker Question

More information

Notes on Electricity (Circuits)

Notes on Electricity (Circuits) A circuit is defined to be a collection of energy-givers (batteries) and energy-takers (resistors, light bulbs, radios, etc.) that form a closed path (or complete path) through which electrical current

More information

AP Physics C - E & M

AP Physics C - E & M Slide 1 / 27 Slide 2 / 27 AP Physics C - E & M Current, Resistance & Electromotive Force 2015-12-05 www.njctl.org Slide 3 / 27 Electric Current Electric Current is defined as the movement of charge from

More information

1) Two lightbulbs, one rated 30 W at 120 V and another rated 40 W at 120 V, are arranged in two different circuits.

1) Two lightbulbs, one rated 30 W at 120 V and another rated 40 W at 120 V, are arranged in two different circuits. 1) Two lightbulbs, one rated 30 W at 120 V and another rated 40 W at 120 V, are arranged in two different circuits. a. The two bulbs are first connected in parallel to a 120 V source. i. Determine the

More information

Electron Theory of Charge. Electricity. 1. Matter is made of atoms. Refers to the generation of or the possession of electric charge.

Electron Theory of Charge. Electricity. 1. Matter is made of atoms. Refers to the generation of or the possession of electric charge. Electricity Refers to the generation of or the possession of electric charge. There are two kinds of electricity: 1. Static Electricity the electric charges are "still" or static 2. Current Electricity

More information

Current and Resistance. PHY2049: Chapter 26 1

Current and Resistance. PHY2049: Chapter 26 1 Current and Resistance PHY2049: Chapter 26 1 What You Will Learn in This Chapter Nature of electric current Drift speed, current and current density Current and voltage measurements Conductivity and resistivity

More information

Direct Current (DC) Circuits

Direct Current (DC) Circuits Direct Current (DC) Circuits NOTE: There are short answer analysis questions in the Participation section the informal lab report. emember to include these answers in your lab notebook as they will be

More information

Physics 201. Professor P. Q. Hung. 311B, Physics Building. Physics 201 p. 1/3

Physics 201. Professor P. Q. Hung. 311B, Physics Building. Physics 201 p. 1/3 Physics 201 p. 1/3 Physics 201 Professor P. Q. Hung 311B, Physics Building Physics 201 p. 2/3 Summary of last lecture Equipotential surfaces: Surfaces where the potential is the same everywhere, e.g. the

More information

Chapter 21 Electric Current and Direct- Current Circuits

Chapter 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 information

ELECTRICITY. Electric Circuit. What do you already know about it? Do Smarty Demo 5/30/2010. Electric Current. Voltage? Resistance? Current?

ELECTRICITY. Electric Circuit. What do you already know about it? Do Smarty Demo 5/30/2010. Electric Current. Voltage? Resistance? Current? ELECTRICITY What do you already know about it? Voltage? Resistance? Current? Do Smarty Demo 1 Electric Circuit A path over which electrons travel, out through the negative terminal, through the conductor,

More information

Closed loop of moving charges (electrons move - flow of negative charges; positive ions move - flow of positive charges. Nucleus not moving)

Closed 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 information

Electric Current. Chapter 17. Electric Current, cont QUICK QUIZ Current and Resistance. Sections: 1, 3, 4, 6, 7, 9

Electric 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 information

Chapter 16. Current and Drift Speed. Electric Current, cont. Current and Drift Speed, cont. Current and Drift Speed, final

Chapter 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 information

Lecture 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. 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 information

Current. I = ei e = en e Av d. The current, which is Coulomb s per second, is simply

Current. 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 information

6. In a dry cell electrical energy is obtained due to the conversion of:

6. In a dry cell electrical energy is obtained due to the conversion of: 1. If a wire of uniform area of cross section is cut into two halves (equal in size), the resistivity of each part will be: a) Halved. b) Doubled. c) Becomes four times its initial value. d) Remains the

More information

Dynamic Electricity. All you need to be an inventor is a good imagination and a pile of junk. -Thomas Edison

Dynamic Electricity. All you need to be an inventor is a good imagination and a pile of junk. -Thomas Edison Dynamic Electricity All you need to be an inventor is a good imagination and a pile of junk. -Thomas Edison Review Everything is made of atoms which contain POSITIVE particles called PROTONS and NEGATIVE

More information

Electric Currents & Resistance

Electric 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 information

Electroscope Used to are transferred to the and Foil becomes and

Electroscope Used to are transferred to the and Foil becomes and Electricity Notes Chapter 17 Section 1: Electric Charge and Forces Electric charge is a variety of independent all with one single name. Electricity is related to, and both (-) and (+) carry a charge.

More information

Notes on Electricity (Circuits)

Notes on Electricity (Circuits) A circuit is defined to be a collection of energy-givers (active elements) and energy-takers (passive elements) that form a closed path (or complete path) through which electrical current can flow. The

More information

Physics 142 Steady Currents Page 1. Steady Currents

Physics 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 information

physics for you February 11 Page 68

physics 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 information

DEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS

DEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS DEL PHYSCS THE BADDEST CLASS ON CAMPUS B PHYSCS TSOKOS LESSON 5-4: ELECTRC CURRENT AND ELECTRC RESSTANCE Reading Activity Questions? Objectives By the end of this class you should be able to: Q State the

More information

University Physics (PHY 2326)

University 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 information

Electricity. Lily, Laura, Lynette, Elyse, Gillian, Emma, Hailey Period 2. onedio.com

Electricity. Lily, Laura, Lynette, Elyse, Gillian, Emma, Hailey Period 2. onedio.com Electricity Lily, Laura, Lynette, Elyse, Gillian, Emma, Hailey Period 2 onedio.com Electrostatics vs. Electricity Electrostatics is the study of charges at rest Electrostatics: to help remember the difference

More information

ELECTRICITY UNIT REVIEW

ELECTRICITY UNIT REVIEW ELECTRICITY UNIT REVIEW S1-3-04: 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 information

Electric Currents. Resistors (Chapters 27-28)

Electric Currents. Resistors (Chapters 27-28) Electric Currents. Resistors (Chapters 27-28) Electric current I Resistance R and resistors Relation between current and resistance: Ohm s Law Resistivity ρ Energy dissipated by current. Electric power

More information

College Physics B - PHY2054C

College Physics B - PHY2054C Power College - PHY2054C and 09/15/2014 My Office Hours: Tuesday 10:00 AM - Noon 206 Keen Building PHY2054C Power First Mini-Exam this week on Wednesday!! Location: UPL 101, 10:10-11:00 AM Exam on chapters

More information

What does it mean for an object to be charged? What are charges? What is an atom?

What does it mean for an object to be charged? What are charges? What is an atom? What does it mean for an object to be charged? What are charges? What is an atom? What are the components of an atom? Define the following: Electric Conductor Electric Insulator Define the following: Electric

More information

ConcepTest PowerPoints

ConcepTest PowerPoints ConcepTest PowerPoints Chapter 16 Physics: Principles with Applications, 7 th edition Giancoli 2014 Pearson Education, Inc. This work is protected by United States copyright laws and is provided solely

More information

CIRCUITS: Series & Parallel

CIRCUITS: Series & Parallel CIRCUITS: Series & Parallel Last Week s BIG IDEAS: Opposite charged objects attract Like charged objects repel Last Week s BIG IDEAS: The electrons are the loose particles that move to make things charged

More information

Look over Chapter 26 sections 1-7 Examples 3, 7. Look over Chapter 18 sections 1-5, 8 over examples 1, 2, 5, 8, 9,

Look over Chapter 26 sections 1-7 Examples 3, 7. Look over Chapter 18 sections 1-5, 8 over examples 1, 2, 5, 8, 9, Look over Chapter 26 sections 1-7 Examples 3, 7 Look over Chapter 18 sections 1-5, 8 over examples 1, 2, 5, 8, 9, 1)How to find a current in a wire. 2)What the Current Density and Draft Speed are. 3)What

More information

Chapter 33 - Electric Fields and Potential. Chapter 34 - Electric Current

Chapter 33 - Electric Fields and Potential. Chapter 34 - Electric Current Chapter 33 - Electric Fields and Potential Chapter 34 - Electric Current Electric Force acts through a field An electric field surrounds every electric charge. It exerts a force that causes electric charges

More information

Clicker Session Currents, DC Circuits

Clicker Session Currents, DC Circuits Clicker Session Currents, DC Circuits Wires A wire of resistance R is stretched uniformly (keeping its volume constant) until it is twice its original length. What happens to the resistance? 1) it decreases

More information

Current and Resistance

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 2-1 Electric current 2-2

More information

Physics 7B-1 (A/B) Professor Cebra. Winter 2010 Lecture 2. Simple Circuits. Slide 1 of 20

Physics 7B-1 (A/B) Professor Cebra. Winter 2010 Lecture 2. Simple Circuits. Slide 1 of 20 Physics 7B-1 (A/B) Professor Cebra Winter 2010 Lecture 2 Simple Circuits Slide 1 of 20 Conservation of Energy Density In the First lecture, we started with energy conservation. We divided by volume (making

More information

Chapter 17. Current and Resistance. Sections: 1, 3, 4, 6, 7, 9

Chapter 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 information

Electric Current, Resistance and Resistivity. Brief otes

Electric Current, Resistance and Resistivity. Brief otes Electric current, resistance and restivity Electric Current, esistance and esistivity In This small e-book we will learn all we need to know about current electricity but in short and then we ll have some

More information

Section 1 Electric Charge and Force

Section 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 information

1. How does a light bulb work?

1. How does a light bulb work? AP Physics 1 Lesson 12.a Electric Current and Circuits Outcomes 1. Determine the resistance of a resistor given length, cross-sectional area and length. 2. Relate the movement of charge to differences

More information

Chapter 18 Electric Currents

Chapter 18 Electric Currents Chapter 18 Electric Currents 1 The Electric Battery Volta discovered that electricity could be created if dissimilar metals were connected by a conductive solution called an electrolyte. This is a simple

More information

16.1 Electrical Current

16.1 Electrical Current 16.1 Electrical Current Electric Current Electric Current When the ends of an electric conductor are at different electric potentials, charge flows from one end to the other Flow of Charge Charge flows

More information

Engineering Fundamentals and Problem Solving, 6e

Engineering Fundamentals and Problem Solving, 6e Engineering Fundamentals and Problem Solving, 6e Chapter 17 Electrical Circuits Chapter Objectives Compute the equivalent resistance of resistors in series and in parallel Apply Ohm s law to a resistive

More information

Lorik educational academy-vidyanagar

Lorik educational academy-vidyanagar Lorik educational academy-vidyanagar 9849180367 ----------------------------------------------------------------------------------------------------------------------- Section: Senior TOPIC: CURRENT ELECTRICITY

More information

Chapter 21 Electric Current and Direct- Current Circuits

Chapter 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 information

PH 102 Exam I N N N N. 3. Which of the following is true for the electric force and not true for the gravitational force?

PH 102 Exam I N N N N. 3. Which of the following is true for the electric force and not true for the gravitational force? Name Date INSTRUCTIONS PH 102 Exam I 1. nswer all questions below. ll problems have equal weight. 2. Clearly mark the answer you choose by filling in the adjacent circle. 3. There will be no partial credit

More information

Review. Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

Review. Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. Review Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. When more devices are added to a series circuit, the total circuit resistance: a.

More information

and in a simple circuit Part 2

and 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 information

Physics 2102 Gabriela González. Georg Simon Ohm ( )

Physics 2102 Gabriela González. Georg Simon Ohm ( ) Physics 2102 Gabriela González Georg Simon Ohm (1789-1854) E In a conductor, electrons are free to move. If there is a field E inside the conductor, F=qE means the electrons move in a direction opposite

More information

SPH3U1 Lesson 01 Electricity

SPH3U1 Lesson 01 Electricity ELECTRIC CURRENT AND POTENTIAL DIFFERENCE LEARNING GOALS Students will: Define what is meant by electric current. Solve problems involving current, charge and time. Know the difference between electron

More information

ConcepTest PowerPoints

ConcepTest PowerPoints ConcepTest PowerPoints Chapter 19 Physics: Principles with Applications, 6 th edition Giancoli 2005 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for

More information

CLASS X- ELECTRICITY

CLASS X- ELECTRICITY Conductor- Insulator: Materia Materials through which electric current cannot pass are called insulators. Electric Circuit: A continuous a CLASS X- ELECTRICITY als through which electric current can pass

More information

52 VOLTAGE, CURRENT, RESISTANCE, AND POWER

52 VOLTAGE, CURRENT, RESISTANCE, AND POWER 52 VOLTAGE, CURRENT, RESISTANCE, AND POWER 1. What is voltage, and what are its units? 2. What are some other possible terms for voltage? 3. Batteries create a potential difference. The potential/voltage

More information

Current Electricity. ScienceLinks 9, Unit 4 SciencePower 9, Unit 3

Current Electricity. ScienceLinks 9, Unit 4 SciencePower 9, Unit 3 Current Electricity ScienceLinks 9, Unit 4 SciencePower 9, Unit 3 Current Electricity The flow of negative charges (electrons) through conductors Watch the BrainPOPs: Electricity Current Electricity Activity:

More information

AP Physics C. Electric Circuits III.C

AP Physics C. Electric Circuits III.C AP Physics C Electric Circuits III.C III.C.1 Current, Resistance and Power The direction of conventional current Suppose the cross-sectional area of the conductor changes. If a conductor has no current,

More information

For an electric current to flow between two points, two conditions must be met.

For an electric current to flow between two points, two conditions must be met. ELECTROSTATICS LAB Electric Circuits For an electric current to flow between two points, two conditions must be met. 1. There must be a conducting path between the points along which the charges can move.

More information

Continuous flow of electric charges. Current Electricity

Continuous flow of electric charges. Current Electricity Continuous flow of electric charges Current Electricity Did You Know? The voltage across a muscle cell in your body is about 70 millivolts. A millivolt (mv) is one thousandth of a volt. AC and DC DC Direct

More information

Chapter 3: Electric Current and Direct-Current Circuit

Chapter 3: Electric Current and Direct-Current Circuit Chapter 3: Electric Current and Direct-Current Circuit n this chapter, we are going to discuss both the microscopic aspect and macroscopic aspect of electric current. Direct-current is current that flows

More information

Protons = Charge Electrons = Charge Neutrons = Charge. When Protons = Electrons, atoms are said to be ELECTRICALLY NEUTRAL (no net charge)

Protons = Charge Electrons = Charge Neutrons = Charge. When Protons = Electrons, atoms are said to be ELECTRICALLY NEUTRAL (no net charge) QUICK WRITE: For 2 minutes, write the three parts of an atom and what their charges are. Explain what creates an electric charge (positive or negative) on something. Rules - You MUST write for the entire

More information

Circuits-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?

Circuits-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? 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 information

In this unit, we will examine the movement of electrons, which we call CURRENT ELECTRICITY.

In this unit, we will examine the movement of electrons, which we call CURRENT ELECTRICITY. Recall: Chemistry and the Atom! What are the 3 subatomic Where are they found in the particles? atom? What electric charges do they have? How was a positive ion created? How was a negative ion created?

More information

ConcepTest Clicker Questions. Chapter 26 Physics: for Scientists & Engineers with Modern Physics, 4th edition Giancoli

ConcepTest Clicker Questions. Chapter 26 Physics: for Scientists & Engineers with Modern Physics, 4th edition Giancoli ConcepTest Clicker Questions Chapter 26 Physics: for Scientists & Engineers with Modern Physics, 4th edition Giancoli 2008 Pearson Education, Inc. This work is protected by United States copyright laws

More information

= e = e 3 = = 4.98%

= e = e 3 = = 4.98% PHYS 212 Exam 2 - Practice Test - Solutions 1E In order to use the equation for discharging, we should consider the amount of charge remaining after three time constants, which would have to be q(t)/q0.

More information

(b) State the relation between work, charge and potential difference for an electric circuit.

(b) State the relation between work, charge and potential difference for an electric circuit. Question Bank on Ch-Electricity 1. (a) Define the S.I unit of potential difference. (b) State the relation between work, charge and potential difference for an electric circuit. Calculate the potential

More information

Tactics Box 23.1 Using Kirchhoff's Loop Law

Tactics Box 23.1 Using Kirchhoff's Loop Law PH203 Chapter 23 solutions Tactics Box 231 Using Kirchhoff's Loop Law Description: Knight/Jones/Field Tactics Box 231 Using Kirchhoff s loop law is illustrated Learning Goal: To practice Tactics Box 231

More information

Capacitance. A different kind of capacitor: Work must be done to charge a capacitor. Capacitors in circuits. Capacitor connected to a battery

Capacitance. 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 information

Circuit Lab Free Response

Circuit Lab Free Response Circuit Lab Free Response Directions: You will be given 40 minutes to complete the following written portion of the Circuit Lab exam. The following page contains some helpful formulas that you may use

More information

Physics Circuits: Series

Physics Circuits: Series FACULTY OF EDUCATION Department of Curriculum and Pedagogy Physics Circuits: Series Science and Mathematics Education Research Group Supported by UBC Teaching and Learning Enhancement Fund 2012-2013 Series

More information

Chapter 3 Static and Current Electricity

Chapter 3 Static and Current Electricity Chapter 3 Static and Current Electricity 3.1 Static Electricity - the build up of an electronic charge on a body (object) Electroscope - a device for detecting (not measuring) static charge attraction/repulsion

More information

Lecture 7.1 : Current and Resistance

Lecture 7.1 : Current and Resistance Lecture 7.1 : Current and Resistance Lecture Outline: Current and Current Density Conductivity and Resistivity Resistance and Ohm s Law Textbook Reading: Ch. 30.3-30.5 Feb. 26, 2013 1 Announcements By

More information

Chapter 26 & 27. Electric Current and Direct- Current Circuits

Chapter 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 information

Chapter 25 Current, Resistance, and Electromotive Force

Chapter 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 information

Unit 1 Lesson 1.2 Energy Sources

Unit 1 Lesson 1.2 Energy Sources Unit Lesson. Energy Sources ntroduction to Electricity 0 Electricity Movement of electrons nvisible force that provides light, heat, sound, motion... Elements he simplest form of matter Atoms Smallest

More information

Use these circuit diagrams to answer question 1. A B C

Use these circuit diagrams to answer question 1. A B C II Circuit Basics Use these circuit diagrams to answer question 1. B C 1a. One of the four voltmeters will read 0. Put a checkmark beside it. b. One of the ammeters is improperly connected. Put a checkmark

More information

Note on Posted Slides. Flow of Charge. Electricity/Water Analogy: Continuing the Analogy. Electric Current

Note on Posted Slides. Flow of Charge. Electricity/Water Analogy: Continuing the Analogy. Electric Current Note on Posted Slides These are the slides that I intended to show in class on Tue. Mar. 18, 2014. They contain important ideas and questions from your reading. Due to time constraints, I was probably

More information

Voltage Sources. Potential Energy vs. Electric Potential. Clicker Question: Clicker Question:

Voltage Sources. Potential Energy vs. Electric Potential. Clicker Question: Clicker Question: Electrostatics Cont. Physics Open House Wednesday, November 5th Lab Tours! Free Pizza and Soft Drinks! Star Party at Campus Observatory! Learn about the Physics Department and our majors Potential Energy

More information

Chapter 28. Direct Current Circuits

Chapter 28. Direct Current Circuits Chapter 28 Direct Current Circuits Circuit Analysis Simple electric circuits may contain batteries, resistors, and capacitors in various combinations. For some circuits, analysis may consist of combining

More information

Physics 2020 Lab 5 Intro to Circuits

Physics 2020 Lab 5 Intro to Circuits Physics 2020 Lab 5 Intro to Circuits Name Section Tues Wed Thu 8am 10am 12pm 2pm 4pm Introduction In this lab, we will be using The Circuit Construction Kit (CCK). CCK is a computer simulation that allows

More information

Name: Block: Date: NNHS Introductory Physics: MCAS Review Packet #4 Introductory Physics, High School Learning Standards for a Full First-Year Course

Name: Block: Date: NNHS Introductory Physics: MCAS Review Packet #4 Introductory Physics, High School Learning Standards for a Full First-Year Course Introductory Physics, High School Learning Standards for a Full First-Year Course I. C ONTENT S TANDARDS electricity and magnetism. 5.1 Recognize that an electric charge tends to be static on insulators

More information

Lab 8 Simple Electric Circuits

Lab 8 Simple Electric Circuits Lab 8 Simple Electric Circuits INTRODUCTION When we talk about the current in a river, we are referring to the flow of water. Similarly, when we refer to the electric current in a circuit, we are talking

More information

PHYSICS 171. Experiment 3. Kirchhoff's Laws. Three resistors (Nominally: 1 Kilohm, 2 Kilohm, 3 Kilohm).

PHYSICS 171. Experiment 3. Kirchhoff's Laws. Three resistors (Nominally: 1 Kilohm, 2 Kilohm, 3 Kilohm). PHYSICS 171 Experiment 3 Kirchhoff's Laws Equipment: Supplies: Digital Multimeter, Power Supply (0-20 V.). Three resistors (Nominally: 1 Kilohm, 2 Kilohm, 3 Kilohm). A. Kirchhoff's Loop Law Suppose that

More information

Chapter 3: Electric Current And Direct-Current Circuits

Chapter 3: Electric Current And Direct-Current Circuits Chapter 3: Electric Current And Direct-Current 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 information

Relating Voltage, Current and Resistance

Relating Voltage, Current and Resistance Relating Voltage, Current and Resistance Using Ohm s Law in a simple circuit. A Simple Circuit Consists of:! A voltage source often a battery! A load such as a bulb! Conductors arranged to complete a circuit

More information

Electricity and Light Pre Lab Questions

Electricity and Light Pre Lab Questions Electricity and Light Pre Lab Questions The pre lab questions can be answered by reading the theory and procedure for the related lab. You are strongly encouraged to answers these questions on your own.

More information

ELECTRIC CURRENT INTRODUCTION. Introduction. Electric current

ELECTRIC 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 information