Objects usually are charged up through the transfer of electrons from one object to the other.

Size: px
Start display at page:

Download "Objects usually are charged up through the transfer of electrons from one object to the other."

Transcription

1 1 Part 1: Electric Force Review of Vectors Review your vectors! You should know how to convert from polar form to component form and vice versa add and subtract vectors multiply vectors by scalars Find the resultant vector R = r 2 3r 1 where r 1 = 10 m, 45 and r 2 = 20 m, 270. Ans m, Charge Symbol q, Q mks units [Coulomb = C] Fundamental charge e = 1.6x10-19 C Charge of proton q p = +e Charge of electron q e = -e An object is neutral if it has the same number of electrons and protons. An object has a net positive charge if it has more protons than electrons. An object has a net negative charge if it has more electrons than protons. Objects usually are charged up through the transfer of electrons from one object to the other. An object has a net charge of -8 nc. Does it have more protons or electrons? How many more? Ans. The object has 50 billion more electrons than protons.

2 2 1.2 Electric Force & Field q 2 Coulomb s Law describes the electric force between charged objects. Size: F = k q 1q 2 r 2 q 1 Coulomb s constant k = 9x10 9 N m 2 /C 2 r Direction: Opposite charges attract along line r. Like charges repel along line r. Consider the ground state of a H-1 (hydrogen) atom that has one electron orbiting a single proton in the lowest orbit allowed for the electron. Compare the size of the electric force between the electron and proton to that of the gravitational force between the particles. You will need the following information. mass of electron 9.11x10-31 kg mass of proton 1.67x10-27 kg distance between electron and proton in ground state 0.05 nm Are we justified in saying that it is the electric force that holds atoms together and that the gravitational force is negligible in comparison? Ans. electric force ~ 9x10-8 N, gravitational force ~4x10-47 N. The electric force is larger by 39 orders of magnitude. We can definitely ignore gravity. The following three charges are held fixed on an x-y grid. q 1 = -2 C at (0,0) q 2 = +3 C at (2 m,0) q 3 = -4 C at (1 m, -2 m) Find the net force exerted by charges 2 and 3 on charge 1. Ans N, 61.3

3 3 A charged object with charge q o produces an electric field vector E at every point in space except at its position. This object exerts an electrical force on another charged object with charge q. This force is given by F = qe where E is the electric field of the object with charge q o produced at the position of the object with charge q. If q is +, the force points in same direction as the field vector. If q is -, the force points in the opposite direction as the field vector. mks units of electric field [N/C] Electric Field of Point Charges A charged object that can be approximated as a point charge produces an electric field at point P. Size of field: E = k q r 2 Direction of field: If q is +, field vector points away from charge along line r. +q If q is -, field vector points towards charge along line r. The following three charges are held fixed on an x-y grid. -q r x P r x P q 1 = -2 C at (0,0) q 2 = +3 C at (2 m,0) q 3 = -4 C at (1 m, -2 m) Note that this is the same charge distribution used in the previous example in the force section. (a) Find the net electric field at the origin due to these point charges. (b) Find force exerted by charges 2 and 3 on charge 1 by using F = qe and show that this answer is identical to the one you found in the previous example. Ans. (a) 7344 N/C, (b) N, 61.3

4 4 Motion of Charged Particles in E-Fields A charged particle of mass m moving in a region of electric field experiences an acceleration with a size of a = F m = q E m If the electric field is uniform in this region then the acceleration is constant and the equations of motion for constant acceleration can be used to describe the particle s motion. x = x o + v o t at2 v = v o + at v 2 = v o 2 + 2a(x x o ) x = x o (v o + v)t An electron, initially at rest, is accelerated horizontally from left to right by a uniform electric field of 2500 N/C between two metal plates that are separated by 2 cm. After leaving these plates, the electron then enters a uniform field of 1000 N/C oriented vertically with the electric field pointing upwards. (a) Find the speed of the electron as it enters the second field region. (b) Find the position of the electron 2 ns after it enters the second field region. Ans. (a) 4.19x10 6 m/s (b) 8.4 mm to the right and 0.35 mm down

5 5 1.3 Voltage & Potential Energy Potential Energy of Point Charges (Charged Particles) Symbol U mks units [Joules = J] Two point charges share an electric potential energy of U = kq 1q 2 r Coulomb s constant k = 9x10 9 N m 2 /C 2 This potential energy can be used in the Law of Conservation of Energy where K is the kinetic energy of a charged particle. K i + U i = K f + U f An electron is moving at 10 6 m/s and is 1 nm from a heavy positive ion. How fast is the electron moving when it is 10 nm from the ion? The ion is singly ionized, i.e. one electron has been removed from the neutral atom. Assume that the ion is so heavy compared to the electron that the ion does not move. Ans. 7.4x10 5 m/s Voltage (Potential) Symbol V mks units [Volts = V] A charged object with charge q o produces a voltage at every point in space except at its position. This object shares a potential energy with another object with charge q. This energy is given by U = qv where V is the voltage of the object with charge q o produced at the position of the object with charge q.

6 6 Equipotential Surfaces Every point on one equipotential surface is at the same voltage. If a charged particle moves from one equipotential surface to another surface at a different voltage, then the particle will change speed. The Law of Conservation of Energy can be rewritten as K i + qv i = K f + qv f Positive charges speed up when going from high to low voltage. They slow down when going from low to high voltage. Negative charges speed up when going from low to high voltage. They slow down when going from high to low voltage. Using the previous equation, you can write that the amount of kinetic energy gained or lost is K = q V = q V Note that in this equation, V is the absolute value of the voltage difference. Charged Parallel Plates (Uniform Electric Field) There is a uniform electric field E between a set of parallel plates with different amounts of charge. There is then a voltage difference V between the plates given by V = Ed where d is the distance between the plates. This voltage difference is usually is written as just plain V so the equation becomes V = Ed The electric field points from the more positive plate to the more negative plate. The more positive plate is at a higher voltage than the more negative plate. V is the difference between these two plate voltages. +Q + d E V _ -Q

7 7 Note from the above equation that the electric field can be expressed in units of [V/m]. This unit is equivalent to [N/C]. The motion of charged particles between the plates can be analyzed using the previous equation for the kinetic energy gained or lost by the particle as it travels across the plates. K = q V = q V The mks unit of energy is the Joule. The kinetic energies of typical charged particles is much less than a Joule so we introduce another energy unit called the electronvolt [ev] which is defined to be the kinetic energy gained by an electron if it is accelerated across 1 V of voltage difference. [1 ev = 1.6x10-19 J] Two parallel plates are separated by 2 cm. The top plate is at 90V and the bottom plate is at - 10V. You are instructed to accelerate an electron across the plates. Answer the following questions. (a) What is the size of the electric field between the plates? (b) Near which plate should you place the electron so it speeds up as it travels between the plates? (c) How much kinetic energy does the electron gain in traveling across the plates? Answer in units of Joules and electronvolts. (d) What is the final speed of the electron if it starts approximately at rest? Ans. (a) 5000 V/m (b) bottom plate (c) 1.6x10-17 J = 100 ev (d) 5.93x10 6 m/s

8 8 1.4 Capacitance & Capacitors A capacitor is a device that can store opposite charge (+Q and Q) on two different surfaces when a voltage difference (V) is applied between the surfaces. The capacitance (C) of the capacitor determines how much charge can be stored for a given voltage difference. Q = CV In this equation, Q is the absolute value of the charge on one of the surfaces and V is the voltage difference between the surfaces. mks units of capacitance [Farad = F = C/V] The capacitance of a capacitor depends on the shape of the capacitor and the material between the two surfaces. For a parallel-plate capacitor, A C = Κε oa d d where A is the area of one of the plates, d is the distance between the plates, and is the dielectric constant of the insulating material between the plates. The dielectric constant has no units and is a property of the material. A capacitor stores energy in the electric field between the plates with an amount equal to U = 1 2 CV2

9 9 Combinations of Capacitors Capacitors in parallel share the same voltage difference. The equivalent capacitance of two capacitors in parallel is C eq = C 1 + C Capacitors in series store the same amount of charge. The equivalent capacitance of two capacitors in series is given by 1 C eq = 1 C C 2 This equation can be solved for the equivalent capacitance to give C eq= C 1 C 2 C 1 + C 2 (a) Find the equivalent capacitance of the circuit. (b) Find for each capacitor the amount of stored charge, the voltage difference, and the amount of stored energy if a voltage difference of 12 V is applied between points A and B. A C 1 C 2 B C 3 C 1 = 3 F C 2 = 6 F C 3 = 4 F Ans. (a) 6 F (b) C 1 : 24 C, 8 V, 96 J C 2 : 24 C, 4 V, 48 J C 3 : 48 C, 12 V, 288 J

10 Current Symbol mks units I, i [Amperes = Amps = A = C/s] The current is the rate that charge flows from one point to another. I = Δq Δt By convention, current flows in the direction that positive charge would travel in a circuit. (In practice, it is the flow of electrons in the opposite direction that constitutes the current.) 1. 6 Resistance & Resistors When current flows through an object, there is always some resistance to this flow. A resistor is an object through which a current (I) flows when a voltage difference (V) is applied across the ends of the object. The resistance (R) of the resistor determines how much current flows for a given voltage difference. For most objects, I = V / R This equation is an expression of Ohm s Law which is usually written as V = IR mks units of resistance [Ohm = = V/A ] The resistance of a resistor depends on the shape of the resistor and the material from which it is made. R = ρ A A where A is the cross-sectional area of the object, is the object s length, and is the resistivity of the material. mks units of resistivity [ -m]

11 11 A resistor cannot store energy. Rather, it converts all of the electrical energy it receives into heat energy at a rate given by P = IV Recall that the rate that energy is delivered or used is the power P with units of Watts [ W = J/s]. Power = Energy / Time Thus, the amount of energy supplied or used is Energy = Power Time mks unit of energy [J = W s] common unit of electrical energy [kilowatt-hour = kw-hr] [1 kw-hr = 3.6x10 6 J] Combinations of Resistors Resistors in parallel share the same voltage difference. The equivalent resistance of two resistors in parallel is 1 = R eq R 1 R 2 This equation can be solved for the equivalent resistance to give R eq= R 1 R 2 R 1 + R Resistors in series have the same current flowing through each. The equivalent resistance of two resistors in series is given by R eq = R 1 + R 2

12 12 (a) Find the equivalent resistance of the circuit. (b) Find for each resistor the current, the voltage difference, and the dissipated power. R 1 40 V 8 R 2 R Ans. (a) 20 (b) R 1 : 2 A, 16 V, 32 W R 2 : 0.8 A, 24 V, 19.2 W R 3 : 1.2 A, 24 V, 28.8 W

Coulomb 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

1. The diagram shows the electric field lines produced by an electrostatic focussing device.

1. The diagram shows the electric field lines produced by an electrostatic focussing device. Which one of the following diagrams best shows the corresponding equipotential lines? The electric field lines

AP Physics Study Guide Chapter 17 Electric Potential and Energy Name. Circle the vector quantities below and underline the scalar quantities below

AP Physics Study Guide Chapter 17 Electric Potential and Energy Name Circle the vector quantities below and underline the scalar quantities below electric potential electric field electric potential energy

Gen. Phys. II Exam 1 - Chs. 18,19,20 - Electric Fields, Potential, Current Feb. 12, 2018

Gen. Phys. II Exam 1 - Chs. 18,19,20 - Electric Fields, Potential, Current Feb. 12, 2018 Rec. Time Name For full credit, make your work clear. Show formulas used, essential steps, and results with correct

the electrical nature of matter is inherent in its atomic structure E & M atoms are made up of p+, n, and e- the nucleus has p+ and n

Electric Forces and Fields E & M the electrical nature of matter is inherent in its atomic structure atoms are made up of p+, n, and e- a.k.a Electricity and Magnetism the nucleus has p+ and n surrounding

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

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,

PHYSICS 12 NAME: Electrostatics Review

NAME: Electrostatics Review 1. The diagram below shows two positive charges of magnitude Q and 2Q. Which vector best represents the direction of the electric field at point P, which is equidistant from

Exam 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

PHYSICS 12 NAME: Electrostatics Review

NAME: Electrostatics Review 1. The diagram below shows two positive charges of magnitude Q and 2Q. Which vector best represents the direction of the electric field at point P, which is equidistant from

Chapter 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

d) (6) If a third charge q = 2.0 µc is now placed 12.0 cm to the left of Q 1, what magnitude electric force will it experience?

Gen. Phys. II Exam 1 - Chs. 16,17,18A - Electric Fields, Potential, Current Sep. 12, 2013 Name Rec. Instr. Rec. Time For full credit, make your work clear. Show formulas used, essential steps, and results

General Physics (PHY 2140)

General Physics (PHY 2140) Lecture 5 Electrostatics Electrical energy potential difference and electric potential potential energy of charged conductors Capacitance and capacitors http://www.physics.wayne.edu/~apetrov/phy2140/

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.

104 Practice Exam 1-2/21/02

104 Practice Exam 1-2/21/02 1. One mole of a substance contains 6.02 > 10 23 protons and an equal number of electrons. If the protons could somehow be separated from the electrons and placed in separate

Chapter 16 Electrical Energy Capacitance. HW: 1, 2, 3, 5, 7, 12, 13, 17, 21, 25, 27 33, 35, 37a, 43, 45, 49, 51

Chapter 16 Electrical Energy Capacitance HW: 1, 2, 3, 5, 7, 12, 13, 17, 21, 25, 27 33, 35, 37a, 43, 45, 49, 51 Electrical Potential Reminder from physics 1: Work done by a conservative force, depends only

Electric 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,

Electrical energy & Capacitance

Electrical energy & Capacitance PHY232 Remco Zegers zegers@nscl.msu.edu Room W109 cyclotron building http://www.nscl.msu.edu/~zegers/phy232.html work previously A force is conservative if the work done

Al-Saudia Virtual Academy Pakistan Online Tuition Online Tutor Pakistan Electricity

Al-Saudia Virtual Academy Pakistan Online Tuition Online Tutor Pakistan Electricity ELECTRIC NATURE OF MATTER: The electric nature of matter means the ability of a matter to produce charge on it. The addition

Test Review Electricity

Name: Date: 1. An operating television set draws 0.71 ampere of current when connected to a 120-volt outlet. Calculate the time it takes the television to consume 3.0 10 5 joules of electric energy. [Show

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

and the charge on a proton is +e. We never see objects that have a charge which is not a whole number multiple of this number.

Name: Physics Chapter 17 Study Guide ----------------------------------------------------------------------------------------------------- Useful Information: e = 1.6"10 #19 C k = 9 "10 9 Nm 2 C 2 \$ 0

Electricity

Electricity Electric Charge There are two fundamental charges in the universe. Positive (proton) has a charge of +1.60 x 10-19 C Negative (electron) has a charge of 1.60 x 10-19 C There is one general

2. Basic Components and Electrical Circuits

1 2. Basic Components and Electrical Circuits 2.1 Units and Scales The International System of Units (SI) defines 6 principal units from which the units of all other physical quantities can be derived

Electrostatics and Charge. Creating Electric Fields

Electrostatics and Charge Creating Electric Fields Electric Charges Recall that all matter is made of atoms. Neutral atoms can acquire a charge in several different ways, all of which require movement

Chapter 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

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

melectron= 9.1x10-31 kg e = 1.6x10-19 C MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Exam #1, PHYS 102 Name Chapters 16, 17, & 18 8 February 2006 Constants k=9x109 Nm2/C2 e o =8.85x10-12 F/m mproton=1.673x10-27 kg melectron= 9.1x10-31 kg e = 1.6x10-19 C MULTIPLE CHOICE. Choose the one

Which of these particles has an electrical charge?

Which of these particles has an electrical charge? A. Proton. B. Electron. C. Ion. D. All of the above. Which is the predominant carrier of charge in copper wire? A. Proton. B. Electron. C. Ion. D. All

ALABAMA SCHOOL OF FINE ART, 8 TH GRADE HONORS PHYSICS QUIZ : ELECTROSTATICS TIME: 90 MINUTES NAME

1 ALABAMA SCHOOL OF FINE ART, 8 TH GRADE HONORS PHYSICS QUIZ 4-18-2016: ELECTROSTATICS TIME: 90 MINUTES NAME COVERAGE: ELECTRIC CHARGE, ELECTROSTATIC FORCE (COULOMB S LAW ), ELECTRIC POTENTIAL, ELECTRIC

Theme Music: Duke Ellington Take the A Train Cartoon: Bill Amend FoxTrot

May18, 2011 Physics 122 Prof. E. F. Redish Theme Music: Duke Ellington Take the A Train Cartoon: Bill Amend FoxTrot 1 Review sheets for Final Exam Material from two previous exams plus Electric currents

CHAPTER 1 ELECTRICITY

CHAPTER 1 ELECTRICITY Electric Current: The amount of charge flowing through a particular area in unit time. In other words, it is the rate of flow of electric charges. Electric Circuit: Electric circuit

Electrical energy & Capacitance

Electrical energy & Capacitance PHY232 Remco Zegers zegers@nscl.msu.edu Room W109 cyclotron building http://www.nscl.msu.edu/~zegers/phy232.html work previously A force is conservative if the work done

Electric 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

Capacitance, Resistance, DC Circuits

This test covers capacitance, electrical current, resistance, emf, electrical power, Ohm s Law, Kirchhoff s Rules, and RC Circuits, with some problems requiring a knowledge of basic calculus. Part I. Multiple

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

Introduction to Charges. BCLN PHYSICS 12 - Rev. Sept/2012

Electrostatics ~ Learning Guide Name: Instructions: Using a pencil, answer the following questions. The Pre-Reading is marked, based on effort, completeness, and neatness (not accuracy). The rest of the

Science Olympiad Circuit Lab Key Concepts Circuit Lab Overview Circuit Elements & Tools Basic Relationships (I, V, R, P) Resistor Network Configurations (Series & Parallel) Kirchhoff s Laws Examples Glossary

Electric Potential Energy

Electric Potential Energy the electric potential energy of two charges depends on the distance between the charges when two like charges are an infinite distance apart, the potential energy is zero An

Objects can be charged by rubbing

Electrostatics Objects can be charged by rubbing Charge comes in two types, positive and negative; like charges repel and opposite charges attract Electric charge is conserved the arithmetic sum of the

Chapter 17 Lecture Notes

Chapter 17 Lecture Notes Physics 2424 - Strauss Formulas: qv = U E W = Fd(cosθ) W = - U E V = Ed V = kq/r. Q = CV C = κε 0 A/d κ = E 0 /E E = (1/2)CV 2 Definition of electric potential Definition of Work

Physics 213: General Physics Fall :30 AM Lecture

Physics 213: General Physics Fall 2004 9:30 AM Lecture Midterm I Solutions Tuesday, September 21, 2004 Chem-Phys 153 Name (print): Signature: Student Number: Your Seat Number (on back of chair): 1. Immediately

ELECTROSTATIC FIELDS

ELECTROSTATIC FIELDS Electric charge Ordinary matter is made up of atoms which have positively charged nuclei and negatively charged electrons surrounding them. A body can become charged if it loses or

Physics 2020: Sample Problems for Exam 1

Physics 00: Sample Problems for Eam 1 1. Two particles are held fied on the -ais. The first particle has a charge of Q 1 = 6.88 10 5 C and is located at 1 = 4.56 m on the -ais. The second particle has

Electric Potential Energy & Electric Potential

Electric Potential Energy & Electric Potential Consider the following scenario. F E F E pt.a If we release the ve charge from pt.a The ELECTRIC FIELD produced by the ve charge pulls the ve charge to the

Which of the following is the SI unit of gravitational field strength?

T5-2 [122 marks] 1. A cell is connected in series with a 2.0Ω resistor and a switch. The voltmeter is connected across the cell and reads 12V when the switch is open and 8.0V when the switch is closed.

Electric 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

Chapter 21 Electrical Properties of Matter

Chapter 21 Electrical Properties of Matter GOALS When you have mastered the contents of this chapter, you will be able to achieve the following goals: Definitions Define each of the following terms, and

Physics 12 ELECTROSTATICS

Physics 12 ELECTROSTATICS F = kq 1Q 2 r2 E = V d V = kq r E p = kq 1Q 2 r F = qe V = E p Q 1 000 000 Volts 1 000 000 Volts NAME: Block: Text References 3 rd Ed. Giancolli Pg. 416-30 4 th Ed. Giancolli

AP Physics 2 Summer Assignment (2014)

Name: Date: AP Physics 2 Summer Assignment (2014) Instructions: 1. Read and study Chapter 16 Electric Charge and Electric Field. 2. Answer the questions below. Some questions may require you to use your

Chapter Assignment Solutions

Chapter 20-21 Assignment Solutions Table of Contents Page 558 #22, 24, 29, 31, 36, 37, 40, 43-48... 1 Lightning Worksheet (Transparency 20-4)... 4 Page 584 #42-46, 58-61, 66-69, 76-79, 84-86... 5 Chapter

Physics 102: Lecture 05 Circuits and Ohm s Law

Physics 102: Lecture 05 Circuits and Ohm s Law Physics 102: Lecture 5, Slide 1 Summary of Last Time Capacitors Physical C = ke 0 A/d C=Q/V Series 1/C eq = 1/C 1 + 1/C 2 Parallel C eq = C 1 + C 2 Energy

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

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

Physics 126 Fall 2004 Practice Exam 1. Answer will be posted about Oct. 5.

Physics 126 Fall 2004 Practice Exam 1. Answer will be posted about Oct. 5. 1. Which one of the following statements best explains why tiny bits of paper are attracted to a charged rubber rod? A) Paper

Review from yesterday. Please answer PROBLEM 3 in Knight on page 716 while we are waiting to start. It takes 3.0 μj to move a 15nC charge from A

Review from yesterday Please answer PROBLEM 3 in Knight on page 716 while we are waiting to start. It takes 3.0 μj to move a 15nC charge from A to B 1 Review from yesterday Please answer PROBLEM 17 in

ELECTRICITY & MAGNETISM CHAPTER 8

ELECTRICITY & MAGNETISM CHAPTER 8 E & M - Focus Electric Charge & Force Magnetism Current, Voltage & Power Electromagnetism Simple Electrical Circuits Voltage & Current Transformation Electric Charge &

Circuits Capacitance of a parallel-plate capacitor : C = κ ε o A / d. (ρ = resistivity, L = length, A = cross-sectional area) Resistance : R = ρ L / A

k = 9.0 x 109 N m2 / C2 e = 1.60 x 10-19 C ε o = 8.85 x 10-12 C2 / N m2 Coulomb s law: F = k q Q / r2 (unlike charges attract, like charges repel) Electric field from a point charge : E = k q / r2 ( towards

5. ELECTRIC CURRENTS

5. ELECTRIC CURRENTS TOPIC OUTLINE Section Recommended Time Giancoli Section 5.1 Potential Difference, Current, Resistance 5.2 Electric Circuits 3h 19.1, 19.2 6.2 Electric Field and Force 6.3 Magnetic

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

Louisiana 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),

Practice Exam 1. Necessary Constants and Equations: Electric force (Coulomb s Law): Electric field due to a point charge:

Practice Exam 1 Necessary Constants and Equations: Electric force (Coulomb s Law): Electric field due to a point charge: Electric potential due to a point charge: Electric potential energy: Capacitor energy:

Electrostatics Notes 2 Electric Field on a Single Charge

Electrostatics Notes 2 Electric Field on a Single Charge There are many similarities between gravitational and electrostatic forces. One such similarity is that both forces can be exerted on objects that

ELECTRONICS E # 1 FUNDAMENTALS 2/2/2011

FE Review 1 ELECTRONICS E # 1 FUNDAMENTALS Electric Charge 2 In an electric circuit it there is a conservation of charge. The net electric charge is constant. There are positive and negative charges. Like

Chapter 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

CAPACITORS / ENERGY STORED BY CAPACITORS / CHARGING AND DISCHARGING

PHYSICS A2 UNIT 4 SECTION 3: CAPACITANCE CAPACITORS / ENERGY STORED BY CAPACITORS / CHARGING AND DISCHARGING # Question CAPACITORS 1 What is current? Current is the rate of flow of charge in a circuit

Physics 222, Spring 2010 Quiz 3, Form: A

Physics 222, Spring 2010 Quiz 3, Form: A Name: Date: Instructions You must sketch correct pictures and vectors, you must show all calculations, and you must explain all answers for full credit. Neatness

COLLEGE PHYSICS Chapter 19 ELECTRIC POTENTIAL AND ELECTRIC FIELD

COLLEGE PHYSICS Chapter 19 ELECTRIC POTENTIAL AND ELECTRIC FIELD Electric Potential Energy and Electric Potential Difference It takes work to move a charge against an electric field. Just as with gravity,

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

Electricity Courseware Instructions

Physics Electricity Courseware Instructions This courseware acts as a supplement to the classroom instruction. The five sections on the following slide link to the topic areas. Following the topic area

1.2 Energy of Charged Particles

1.2 Energy of Charged Particles Objective 1: Recall Coulomb s Law which states that the electrostatic force between 2 charged particles is inversely proportional to the square of the distance between them.

Section 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.

Electricity Final Unit Final Assessment

Electricity Final Unit Final Assessment Name k = 1/ (4pe 0 ) = 9.0 10 9 N m 2 C -2 mass of an electron = 9.11 10-31 kg mass of a proton = 1.67 10-27 kg G = 6.67 10-11 N m 2 kg -2 C = 3 x10 8 m/s Show all

Chapter 19: Electric Potential & Potential Energy

Chapter 9: Electric Potential & Potential Energy Brent Royuk Phys-2 Concordia University Terminology Two Different uantities: Electric Potential and Electric Potential Energy Electric Potential = Voltage

Electricity CHARGE. q = 1.6 x10-19 C

Electricity CHARGE q = 1.6 x10-19 C How many protons in a Coulomb? -19 1.00 C x (1 proton) / (1.60 x 10 C) = 18 6.25x10 protons! Opposites Attract Most materials are Electrically NEUTRAL (lowest potential

Electric Charge. Electric Charge ( q ) unbalanced charges positive and negative charges. n Units Coulombs (C)

Electric Charge Electric Charge ( q ) unbalanced charges positive and negative charges n Units Coulombs (C) Electric Charge How do objects become charged? Types of materials Conductors materials in which

DE1.3 - Electronics 1

Engineering Analysis 1 A course for First Year Design Engineering Peter Cheung Department of Electrical & Electronic Engineering Imperial College London URL: www.ee.ic.ac.uk/pcheung/teaching/de1_ee/ E-mail:

PHYS 212 Final Exam (Old Material) Solutions - Practice Test

PHYS 212 Final Exam (Old Material) Solutions - Practice Test 1E If the ball is attracted to the rod, it must be made of a conductive material, otherwise it would not have been influenced by the nearby

Electric Fields Electric charges exert forces on each other when they are a distance apart. The word Electric field is used to explain this action at

Electricity & Magnetism Electric Fields Marline Kurishingal Electric Fields Electric charges exert forces on each other when they are a distance apart. The word Electric field is used to explain this action

Electricity -1. q p = C. q e

Electricity -1 The Electric Charge: As far as electricity concerned there are three kinds of particles: negatively electric charged particles (like electron) positively charged particles (like proton)

PHYSICS - Electrostatics

PHYSICS - Electrostatics Electrostatics, or electricity at rest, involves electric charges, the forces between them, and their behavior in materials. 22.1 Electrical Forces and Charges The fundamental

Class 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

Chapter 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

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,

PHY 101 Practice Exam III Monday, November 27, 2:15-3:35PM

1 PHY 101 Practice Exam III Monday, November 27, 2:15-3:35PM Please be sure to show your work where it is requested. If no work is shown where it is requested, you will not receive any points. Partial

10 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 + + + + + + + - - -

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

KE = 8 10 J d) 2.4 x B 50V e) 1.14 x J

Phys 4: College Physics Key Name MULTPLE CHOCE 1) 4 How much kinetic energy will an electron need to get from point (at a potential of +0 ) to point B (at a potential of +50 ) in the figure below? 0 a)

Phys 2025, First Test. September 20, minutes Name:

Phys 05, First Test. September 0, 011 50 minutes Name: Show all work for maximum credit. Each problem is worth 10 points. Work 10 of the 11 problems. k = 9.0 x 10 9 N m / C ε 0 = 8.85 x 10-1 C / N m e

Agenda 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

Chapter 12 Electrostatic Phenomena

Chapter 12 Electrostatic Phenomena 1. History Electric Charge The ancient Greeks noticed that if you rubbed amber (petrified tree resin) on fur, then the amber would have a property that it could attract

A Review of Circuitry

1 A Review of Circuitry There is an attractive force between a positive and a negative charge. In order to separate these charges, a force at least equal to the attractive force must be applied to one

PHY2054 Summer 2006 Exam 1 06 June 2006

PHY2054 Summer 2006 Exam 1 06 June 2006 Solutions Unless otherwise indicated, (1) is the correct answer. Solutions are, of necessity (due to the writer's self-taught & primitive word-processing skills),

4 r 2. r 2. Solved Problems

CHAP. 24] COULOMB'S LAW AND ELECTRIC FIELDS 233 AN ELECTRIC FIELD is said to exist at any point in space when a test charge, placed at that point, experiences an electrical force. The direction of the

Electric Potential Energy & Electric Potential

Electric Potential Energy & Electric Potential Consider the following scenario. F E F E pt.a If we release the ve charge from pt.a The ELECTRIC FIELD produced by the ve charge pulls the ve charge to the

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

This week. 3/23/2017 Physics 214 Summer

This week Electrical Circuits Series or parallel that s the question. Current, Power and Energy Why does my laptop battery die? Transmission of power to your home Why do we have big transmission towers?

This week. 6/2/2015 Physics 214 Summer

This week Electrical Circuits Series or parallel that s the question. Current, Power and Energy Why does my laptop battery die? Transmission of power to your home Why do we have big transmission towers?