Part 4: Electromagnetism. 4.1: Induction. A. Faraday's Law. The magnetic flux through a loop of wire is
|
|
- Joel Clark
- 6 years ago
- Views:
Transcription
1 1 Part 4: Electromagnetism 4.1: Induction A. Faraday's Law The magnetic flux through a loop of wire is Φ = BA cos θ B A B = magnetic field penetrating loop [T] A = area of loop [m 2 ] = angle between field vector and a vector perpendicular to the plane of the loop mks units of flux [T-m 2 = Weber = Wb] If we define the area vector A as a vector perpendicular to the plane of the loop and with a size equal to the area of the loop, then the flux can be written as Φ = B A Faraday s Law of Induction states that a voltage difference is induced across the ends of a coil of N turns if the magnetic flux through the coil changes. V ind = N Φ Δt If the time interval approaches zero, then you can write that V ind = N dφ dt V = absolute value of the voltage difference [V] N = number of turns in the coil = magnetic flux through one coil [Wb] If the ends of the coil are connected such that a current can flow through the coil and the coil has resistance, then there is an induced current given by Ohm s Law. I ind = V ind
2 2 Example: A coil has 100 turns and each turn has an area of 5 cm 2. The coil is sitting in a uniform magnetic field of 0.3 Teslas where the field direction is perpendicular to the plane of each loop. The field is turned off in half of a second. Find the average induced voltage across the coil and the average induced current that flows through it. Ans. 30 mv and 2 ma The direction of the induced current is given by Lenz s Law. The induced current will flow in a direction that produces a magnetic field that opposes the change in the magnetic flux. Example: We did many examples of Lenz s law in class. You can also practice applying it in the computer problem entitled Induction (Lenz s Law).
3 3 B. AC Generators A generator consists of a coil that is rotated in a magnetic field. A time-varying voltage difference that regularly changes polarity is produced of the form V(t) = V M sin(ωt) V M = amplitude of the voltage [V] = angular frequency of the rotation [rad/s] Note that = 2 f where f is the frequency in units of cycles per time [cycle/s = Hertz =Hz]. The amplitude of the voltage depends on the number of turns in the coil, the area of each turn, the size of the magnetic field, and the frequency of the rotation. V M = NBAω The voltage is sinusoidal in time as the plot shows. V T 0 V M t A positive voltage difference is for one polarity and a negative voltage difference for the other polarity. T = period = time for one cycle [s] T = 1/f The root mean square or rms voltage represents an average that is useful in analysis. For a sinusoidal voltage signal V rms = V M 2
4 4 4.2 Maxwell s Equations The integral forms of Maxwell s Equations are written below. The emphasis in this class is not on calculating the integrals but rather on understanding the physics expressed in the equations. Gauss s Law for Electricity Electric field lines E da = q in ε The Physics: The electric flux through a closed surface is proportional to the net charge inside the surface. The source of electric field is charge. The charge of a single object can be positive, negative, or zero. Gauss s Law for Magnetism B da = 0 The Physics: The magnetic flux through a closed surface is zero. Magnetic field lines form closed loops. There are no magnetic monopoles. Faraday s Law E ds = d dt ( B da ) Magnetic field lines Magnetic field lines The Physics: An electric field is induced in a region where there is a changing magnetic field. Ampere-Maxwell Law I B ds = μi + με d dt ( E da ) Electric field lines The Physics: A current (moving charge) creates a magnetic field. A magnetic field can also be induced in a region where there is a changing electric field.
5 5 4.3 Inductance & Inductors A inductor is a device that develops a voltage difference between the ends of the device when the current (I) through it changes. The inductance (L) of the inductor determines the size of the induced voltage (V). V = L I Δt If the time interval approaches zero, then you can write that V = L di dt In this equation, I is the current and V is the size of the induced voltage. mks units of inductance [Henry = H = V s/a = s] The inductance of an inductor depends on the shape of the inductor and the material at its core. For a long solenoid, L = μn2 A l A N turns where N is the number of turns, A is the area of one of the turns, is the length of the coil, and is the magnetic permeability of the core. If the core is free space, = o = 4 x10-7 T m/a. An inductor stores energy in its magnetic field as long as a current flows through the inductor. U = 1 2 LI2
6 6 Transformer A transformer consists of two separate coils wrapped a common ferromagnetic core. An ac voltage difference supplied to the primary coil results in an induced ac voltage signal across the secondary coil. V 2 = N 2 N 1 V 1 V 1 = average voltage supplied to primary coil N 1 = number of turns in primary coil V 2 = average voltage across secondary coil N 2 = number of turns in secondary coil The transformer must obey the Law of Conservation of Energy. Some energy is always lost in the core due to the heating of the core from induced eddy currents. Thus, the average output power of the secondary coil is less that the average input power used by the primary coil. P 2 = ηp 1 = power efficiency of transformer ( < 1) The average power can be written as P = IV so the transformer power equation can be written as I 2 V 2 = ηi 1 V 1 Example: A step-up transformer with a turn ratio of 4 is used to power a motor. The primary side of the transformer uses 10 V. When connected to the transformer, the motor draws ma from the secondary coil. The power efficiency of the transformer is 95%. Find (a) the voltage difference supplied to the motor and (b) the current that flows into the primary side. Ans. (a) 40 V (b) 1 A
7 7 4.4 DC Circuits with Inductors L Circuits Close switch at t = 0 Turning on a current: Current increases in size to its final value of V o /. V o L I(t) = V o (1 e t τ) Turning off a current: Current through resistor decreases with time to zero. Simultaneously open switch 1 and close switch 2 at t = 0 1 I(t) = V o e t τ V o 2 L In both cases, is the L time constant: = L / [s] The current reaches its final value after about 5 time constants. LC Circuit A fully charged capacitor with an initial charge of Q on its plates is discharge through a pure inductance. The charge on a plate and the current flowing through the circuit oscillate at the same angular frequency of according to q(t) = Q cos(ωt) I(t) = dq dt = ωq sin(ωt) where the natural oscillation frequency is ω = 1 LC C Close switch at t = 0 L
8 8 4.5 AC Circuits Consider a sinusoidal voltage signal from an ac supply of the form V(t) = V M sin(ωt) When this supply is connected to a single device (a resistor, capacitor, or inductor), the ac current that flows will be of the form and where I(t) = I M sin(ωt + ) I M = V M X = phase angle between current and voltage [rads] X = reactance of device [ ] Device X ( ) (rads) esistor 0 current in phase with voltage Capacitor 1/( C) /2 current leads voltage Inductor L - /2 current lags voltage If the supply is connected to more than one device, then the current will be of the same form and the reactance of the circuit is called the impedance. and where I(t) = I M sin(ωt + ) I M = V M Z = phase angle between current and voltage [rads] Z = impedance of circuit [ ] The phase angle and impedance depend on the type of devices in the circuit and how they are connected. Since the rms value is proportional to the amplitude, we can also write I rms = V rms Z
9 9 Average power delivered to circuit: P ave = I rms V rms cos φ Example: LC Series Z = 2 + (ωl 1/ωC) 2 tan φ = ωl 1/ωC P ave = V rms 2 2 Z 2 = I rms At resonance, the impedance is minimized and the rms current and average power are at their maximum values. The current and voltage signals are in phase ( = 0). esonant frequency: ω o = 1 Minimum impedance: LC Z min = Maximum rms current: V rms L I rms max = V rms C Maximum average power: P ave max = V 2 rms
10 10 Example: An LC series circuit uses a 250-Ohm resistor, a 0.6-Henry inductor, and a 3.5-microFarad capacitor. It is connected to an ac voltage supply operating at 60 Hz with an amplitude of 150 V. Find the following: (a) rms voltage of the supply (b) reactances of the individual devices. (c) impedance of the circuit. (d) rms current flowing through the circuit (e) average power delivered to circuit (f) resonant frequency of the circuit in Hz (g) rms current at resonance (h) average power at resonance Ans. (a) 106 V (b) : 250 L: 226 C: 758 (c) 588 (d) 180 ma (e) 81 W (f) 110 Hz (g) 424 ma (h) 81 W
ELECTROMAGNETIC OSCILLATIONS AND ALTERNATING CURRENT
Chapter 31: ELECTROMAGNETIC OSCILLATIONS AND ALTERNATING CURRENT 1 A charged capacitor and an inductor are connected in series At time t = 0 the current is zero, but the capacitor is charged If T is the
More informationCh. 23 Electromagnetic Induction, AC Circuits, And Electrical Technologies
Ch. 23 Electromagnetic Induction, AC Circuits, And Electrical Technologies Induced emf - Faraday s Experiment When a magnet moves toward a loop of wire, the ammeter shows the presence of a current When
More informationElectromagnetic Induction Faraday s Law Lenz s Law Self-Inductance RL Circuits Energy in a Magnetic Field Mutual Inductance
Lesson 7 Electromagnetic Induction Faraday s Law Lenz s Law Self-Inductance RL Circuits Energy in a Magnetic Field Mutual Inductance Oscillations in an LC Circuit The RLC Circuit Alternating Current Electromagnetic
More informationELECTROMAGNETIC INDUCTION
ELECTROMAGNETIC INDUCTION 1. Magnetic Flux 2. Faraday s Experiments 3. Faraday s Laws of Electromagnetic Induction 4. Lenz s Law and Law of Conservation of Energy 5. Expression for Induced emf based on
More informationGet Discount Coupons for your Coaching institute and FREE Study Material at ELECTROMAGNETIC INDUCTION
ELECTROMAGNETIC INDUCTION 1. Magnetic Flux 2. Faraday s Experiments 3. Faraday s Laws of Electromagnetic Induction 4. Lenz s Law and Law of Conservation of Energy 5. Expression for Induced emf based on
More informationHandout 10: Inductance. Self-Inductance and inductors
1 Handout 10: Inductance Self-Inductance and inductors In Fig. 1, electric current is present in an isolate circuit, setting up magnetic field that causes a magnetic flux through the circuit itself. This
More informationChapter 33. Alternating Current Circuits
Chapter 33 Alternating Current Circuits 1 Capacitor Resistor + Q = C V = I R R I + + Inductance d I Vab = L dt AC power source The AC power source provides an alternative voltage, Notation - Lower case
More informationSUMMARY Phys 2523 (University Physics II) Compiled by Prof. Erickson. F e (r )=q E(r ) dq r 2 ˆr = k e E = V. V (r )=k e r = k q i. r i r.
SUMMARY Phys 53 (University Physics II) Compiled by Prof. Erickson q 1 q Coulomb s Law: F 1 = k e r ˆr where k e = 1 4π =8.9875 10 9 N m /C, and =8.85 10 1 C /(N m )isthepermittivity of free space. Generally,
More informationELECTROMAGNETIC INDUCTION AND FARADAY S LAW
ELECTROMAGNETIC INDUCTION AND FARADAY S LAW Magnetic Flux The emf is actually induced by a change in the quantity called the magnetic flux rather than simply py by a change in the magnetic field Magnetic
More informationSliding Conducting Bar
Motional emf, final For equilibrium, qe = qvb or E = vb A potential difference is maintained between the ends of the conductor as long as the conductor continues to move through the uniform magnetic field
More informationYell if you have any questions
Class 31: Outline Hour 1: Concept Review / Overview PRS Questions possible exam questions Hour : Sample Exam Yell if you have any questions P31 1 Exam 3 Topics Faraday s Law Self Inductance Energy Stored
More informationExam 3 Topics. Displacement Current Poynting Vector. Faraday s Law Self Inductance. Circuits. Energy Stored in Inductor/Magnetic Field
Exam 3 Topics Faraday s Law Self Inductance Energy Stored in Inductor/Magnetic Field Circuits LR Circuits Undriven (R)LC Circuits Driven RLC Circuits Displacement Current Poynting Vector NO: B Materials,
More informationGen. Phys. II Exam 2 - Chs. 21,22,23 - Circuits, Magnetism, EM Induction Mar. 5, 2018
Gen. Phys. II Exam 2 - Chs. 21,22,23 - Circuits, Magnetism, EM Induction Mar. 5, 2018 Rec. Time Name For full credit, make your work clear. Show formulas used, essential steps, and results with correct
More informationRLC Circuit (3) We can then write the differential equation for charge on the capacitor. The solution of this differential equation is
RLC Circuit (3) We can then write the differential equation for charge on the capacitor The solution of this differential equation is (damped harmonic oscillation!), where 25 RLC Circuit (4) If we charge
More informationDriven RLC Circuits Challenge Problem Solutions
Driven LC Circuits Challenge Problem Solutions Problem : Using the same circuit as in problem 6, only this time leaving the function generator on and driving below resonance, which in the following pairs
More informationGeneral Physics (PHY 2140)
General Physics (PHY 2140) Lecture 10 6/12/2007 Electricity and Magnetism Induced voltages and induction Self-Inductance RL Circuits Energy in magnetic fields AC circuits and EM waves Resistors, capacitors
More informationInductance, RL and RLC Circuits
Inductance, RL and RLC Circuits Inductance Temporarily storage of energy by the magnetic field When the switch is closed, the current does not immediately reach its maximum value. Faraday s law of electromagnetic
More informationAlternating Current Circuits
Alternating Current Circuits AC Circuit An AC circuit consists of a combination of circuit elements and an AC generator or source. The output of an AC generator is sinusoidal and varies with time according
More informationAssessment Schedule 2015 Physics: Demonstrate understanding of electrical systems (91526)
NCEA Level 3 Physics (91526) 2015 page 1 of 6 Assessment Schedule 2015 Physics: Demonstrate understanding of electrical systems (91526) Evidence Q Evidence Achievement Achievement with Merit Achievement
More informationGeneral Physics (PHY 2140)
General Physics (PHY 40) eminder: Exam this Wednesday 6/3 ecture 0-4 4 questions. Electricity and Magnetism nduced voltages and induction Self-nductance Circuits Energy in magnetic fields AC circuits and
More informationSelf-Inductance. Φ i. Self-induction. = (if flux Φ 1 through 1 loop. Tm Vs A A. Lecture 11-1
Lecture - Self-Inductance As current i through coil increases, magnetic flux through itself increases. This in turn induces back emf in the coil itself When current i is decreasing, emf is induced again
More informationChapter 21 Magnetic Induction Lecture 12
Chapter 21 Magnetic Induction Lecture 12 21.1 Why is it called Electromagnetism? 21.2 Magnetic Flux and Faraday s Law 21.3 Lenz s Law and Work-Energy Principles 21.4 Inductance 21.5 RL Circuits 21.6 Energy
More informationElectromagnetic Induction (Chapters 31-32)
Electromagnetic Induction (Chapters 31-3) The laws of emf induction: Faraday s and Lenz s laws Inductance Mutual inductance M Self inductance L. Inductors Magnetic field energy Simple inductive circuits
More informationChapter 30 Inductance
Chapter 30 Inductance In this chapter we investigate the properties of an inductor in a circuit. There are two kinds of inductance mutual inductance and self-inductance. An inductor is formed by taken
More informationChapter 31. Faraday s Law
Chapter 31 Faraday s Law 1 Ampere s law Magnetic field is produced by time variation of electric field dφ B ( I I ) E d s = µ o + d = µ o I+ µ oεo ds E B 2 Induction A loop of wire is connected to a sensitive
More information20. Alternating Currents
University of hode sland DigitalCommons@U PHY 204: Elementary Physics Physics Course Materials 2015 20. lternating Currents Gerhard Müller University of hode sland, gmuller@uri.edu Creative Commons License
More informationAlternating Currents. The power is transmitted from a power house on high voltage ac because (a) Electric current travels faster at higher volts (b) It is more economical due to less power wastage (c)
More informationCHAPTER 5: ELECTROMAGNETIC INDUCTION
CHAPTER 5: ELECTROMAGNETIC INDUCTION PSPM II 2005/2006 NO. 5 5. An AC generator consists a coil of 30 turns with cross sectional area 0.05 m 2 and resistance 100 Ω. The coil rotates in a magnetic field
More informationChapter 31. Faraday s Law
Chapter 31 Faraday s Law 1 Ampere s law Magnetic field is produced by time variation of electric field B s II I d d μ o d μo με o o E ds E B Induction A loop of wire is connected to a sensitive ammeter
More informationElectromagnetic Oscillations and Alternating Current. 1. Electromagnetic oscillations and LC circuit 2. Alternating Current 3.
Electromagnetic Oscillations and Alternating Current 1. Electromagnetic oscillations and LC circuit 2. Alternating Current 3. RLC circuit in AC 1 RL and RC circuits RL RC Charging Discharging I = emf R
More informationELEC ELE TRO TR MAGNETIC INDUCTION
ELECTRO MAGNETIC INDUCTION Faraday Henry 1791-1867 1797 1878 Laws:- Faraday s Laws :- 1) When ever there is a change in magnetic flux linked with a coil, a current is generated in the coil. The current
More informationAlternating Current. Symbol for A.C. source. A.C.
Alternating Current Kirchoff s rules for loops and junctions may be used to analyze complicated circuits such as the one below, powered by an alternating current (A.C.) source. But the analysis can quickly
More informationCHAPTER 22 ELECTROMAGNETIC INDUCTION
CHAPTER 22 ELECTROMAGNETIC INDUCTION PROBLEMS 47. REASONING AND Using Equation 22.7, we find emf 2 M I or M ( emf 2 ) t ( 0.2 V) ( 0.4 s) t I (.6 A) ( 3.4 A) 9.3 0 3 H 49. SSM REASONING AND From the results
More informationChapter 32. Inductance
Chapter 32 Inductance Joseph Henry 1797 1878 American physicist First director of the Smithsonian Improved design of electromagnet Constructed one of the first motors Discovered self-inductance Unit of
More informationPHYSICS. Chapter 30 Lecture FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E RANDALL D. KNIGHT
PHYSICS FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E Chapter 30 Lecture RANDALL D. KNIGHT Chapter 30 Electromagnetic Induction IN THIS CHAPTER, you will learn what electromagnetic induction is
More informationChapter 31 Electromagnetic Oscillations and Alternating Current LC Oscillations, Qualitatively
Chapter 3 Electromagnetic Oscillations and Alternating Current LC Oscillations, Qualitatively In the LC circuit the charge, current, and potential difference vary sinusoidally (with period T and angular
More informationInductance, RL Circuits, LC Circuits, RLC Circuits
Inductance, R Circuits, C Circuits, RC Circuits Inductance What happens when we close the switch? The current flows What does the current look like as a function of time? Does it look like this? I t Inductance
More informationSelf-inductance A time-varying current in a circuit produces an induced emf opposing the emf that initially set up the time-varying current.
Inductance Self-inductance A time-varying current in a circuit produces an induced emf opposing the emf that initially set up the time-varying current. Basis of the electrical circuit element called an
More informationEXAM 3: SOLUTIONS. B = B. A 2 = BA 2 cos 0 o = BA 2. =Φ(2) B A 2 = A 1 cos 60 o = A 1 2 =0.5m2
EXAM : S Q.The normal to a certain m area makes an angle of 6 o with a uniform magnetic field. The magnetic flux through this area is the same as the flux through a second area that is perpendicular to
More informationAC Circuits Homework Set
Problem 1. In an oscillating LC circuit in which C=4.0 μf, the maximum potential difference across the capacitor during the oscillations is 1.50 V and the maximum current through the inductor is 50.0 ma.
More informationLouisiana State University Physics 2102, Exam 3 April 2nd, 2009.
PRINT Your Name: Instructor: Louisiana State University Physics 2102, Exam 3 April 2nd, 2009. Please be sure to PRINT your name and class instructor above. The test consists of 4 questions (multiple choice),
More informationOscillations and Electromagnetic Waves. March 30, 2014 Chapter 31 1
Oscillations and Electromagnetic Waves March 30, 2014 Chapter 31 1 Three Polarizers! Consider the case of unpolarized light with intensity I 0 incident on three polarizers! The first polarizer has a polarizing
More informationChapter 23 Magnetic Flux and Faraday s Law of Induction
Chapter 23 Magnetic Flux and Faraday s Law of Induction 1 Overview of Chapter 23 Induced Electromotive Force Magnetic Flux Faraday s Law of Induction Lenz s Law Mechanical Work and Electrical Energy Generators
More informationHandout 11: AC circuit. AC generator
Handout : AC circuit AC generator Figure compares the voltage across the directcurrent (DC) generator and that across the alternatingcurrent (AC) generator For DC generator, the voltage is constant For
More information1 Phasors and Alternating Currents
Physics 4 Chapter : Alternating Current 0/5 Phasors and Alternating Currents alternating current: current that varies sinusoidally with time ac source: any device that supplies a sinusoidally varying potential
More informationPhysics 4B Chapter 31: Electromagnetic Oscillations and Alternating Current
Physics 4B Chapter 31: Electromagnetic Oscillations and Alternating Current People of mediocre ability sometimes achieve outstanding success because they don't know when to quit. Most men succeed because
More informationPhysics 142 AC Circuits Page 1. AC Circuits. I ve had a perfectly lovely evening but this wasn t it. Groucho Marx
Physics 142 A ircuits Page 1 A ircuits I ve had a perfectly lovely evening but this wasn t it. Groucho Marx Alternating current: generators and values It is relatively easy to devise a source (a generator
More informationMagnets. Domain = small magnetized region of a magnetic material. all the atoms are grouped together and aligned
Magnetic Fields Magnets Domain = small magnetized region of a magnetic material all the atoms are grouped together and aligned Magnets Ferromagnetic materials domains can be forced to line up by applying
More informationChapter 21 Lecture Notes
Chapter 21 Lecture Notes Physics 2424 - Strauss Formulas: Φ = BA cosφ E = -N Φ/ t Faraday s Law E = Bvl E = NABω sinωt M = (N 2 Φ 2 )/I 1 E 2 = -M I 1 / t L = NΦ/I E = -L I/ t L = µ 0 n 2 A l Energy =
More information12 Chapter Driven RLC Circuits
hapter Driven ircuits. A Sources... -. A ircuits with a Source and One ircuit Element... -3.. Purely esistive oad... -3.. Purely Inductive oad... -6..3 Purely apacitive oad... -8.3 The Series ircuit...
More informationExam 3 Solutions. The induced EMF (magnitude) is given by Faraday s Law d dt dt The current is given by
PHY049 Spring 008 Prof. Darin Acosta Prof. Selman Hershfield April 9, 008. A metal rod is forced to move with constant velocity of 60 cm/s [or 90 cm/s] along two parallel metal rails, which are connected
More informationInductance, Inductors, RL Circuits & RC Circuits, LC, and RLC Circuits
Inductance, Inductors, RL Circuits & RC Circuits, LC, and RLC Circuits Self-inductance A time-varying current in a circuit produces an induced emf opposing the emf that initially set up the timevarying
More informationELECTRO MAGNETIC INDUCTION
ELECTRO MAGNETIC INDUCTION 1) A Circular coil is placed near a current carrying conductor. The induced current is anti clock wise when the coil is, 1. Stationary 2. Moved away from the conductor 3. Moved
More informationε induced Review: Self-inductance 20.7 RL Circuits Review: Self-inductance B induced Announcements
Announcements WebAssign HW Set 7 due this Friday Problems cover material from Chapters 20 and 21 We re skipping Sections 21.1-21.7 (alternating current circuits) Review: Self-inductance induced ε induced
More informationPhysics 240 Fall 2005: Exam #3 Solutions. Please print your name: Please list your discussion section number: Please list your discussion instructor:
Physics 4 Fall 5: Exam #3 Solutions Please print your name: Please list your discussion section number: Please list your discussion instructor: Form #1 Instructions 1. Fill in your name above. This will
More informationb) (4) How large is the current through the 2.00 Ω resistor, and in which direction?
General Physics II Exam 2 - Chs. 19 21 - Circuits, Magnetism, EM Induction - Sep. 29, 2016 Name Rec. Instr. Rec. Time For full credit, make your work clear. Show formulas used, essential steps, and results
More informationREACTANCE. By: Enzo Paterno Date: 03/2013
REACTANCE REACTANCE By: Enzo Paterno Date: 03/2013 5/2007 Enzo Paterno 1 RESISTANCE - R i R (t R A resistor for all practical purposes is unaffected by the frequency of the applied sinusoidal voltage or
More informationChapter 31: AC Circuits
hapter 31: A ircuits A urrents and Voltages In this chapter, we discuss the behior of circuits driven by a source of A. Recall that A means, literally, alternating current. An alternating current is a
More informationINDUCTANCE Self Inductance
NDUTANE 3. Self nductance onsider the circuit shown in the Figure. When the switch is closed the current, and so the magnetic field, through the circuit increases from zero to a specific value. The increasing
More informationPhysics 2020 Exam 2 Constants and Formulae
Physics 2020 Exam 2 Constants and Formulae Useful Constants k e = 8.99 10 9 N m 2 /C 2 c = 3.00 10 8 m/s ɛ = 8.85 10 12 C 2 /(N m 2 ) µ = 4π 10 7 T m/a e = 1.602 10 19 C h = 6.626 10 34 J s m p = 1.67
More informationMaxwell s equations and EM waves. From previous Lecture Time dependent fields and Faraday s Law
Maxwell s equations and EM waves This Lecture More on Motional EMF and Faraday s law Displacement currents Maxwell s equations EM Waves From previous Lecture Time dependent fields and Faraday s Law 1 Radar
More informationApplication Of Faraday s Law
Application Of Faraday s Law Dr Miguel Cavero September 2, 2014 Application Of Faraday s Law September 2, 2014 1 / 23 The PHYS120 Exam will be divided into three sections as follows: Section A: Short Questions
More informationChapter 20: Electromagnetic Induction. PHY2054: Chapter 20 1
Chapter 20: Electromagnetic Induction PHY2054: Chapter 20 1 Electromagnetic Induction Magnetic flux Induced emf Faraday s Law Lenz s Law Motional emf Magnetic energy Inductance RL circuits Generators and
More informationElectrical polarization. Figure 19-5 [1]
Electrical polarization Figure 19-5 [1] Properties of Charge Two types: positive and negative Like charges repel, opposite charges attract Charge is conserved Fundamental particles with charge: electron
More informationPHYS 1441 Section 001 Lecture #23 Monday, Dec. 4, 2017
PHYS 1441 Section 1 Lecture #3 Monday, Dec. 4, 17 Chapter 3: Inductance Mutual and Self Inductance Energy Stored in Magnetic Field Alternating Current and AC Circuits AC Circuit W/ LRC Chapter 31: Maxwell
More informationChapter 30 Inductance and Electromagnetic Oscillations
Chapter 30 Inductance and Electromagnetic Oscillations Units of Chapter 30 30.1 Mutual Inductance: 1 30.2 Self-Inductance: 2, 3, & 4 30.3 Energy Stored in a Magnetic Field: 5, 6, & 7 30.4 LR Circuit: 8,
More informationLast Homework. Reading: Chap. 33 and Chap. 33. Suggested exercises: 33.1, 33.3, 33.5, 33.7, 33.9, 33.11, 33.13, 33.15,
Chapter 33. Electromagnetic Induction Electromagnetic induction is the scientific principle that underlies many modern technologies, from the generation of electricity to communications and data storage.
More informationCircuit Analysis-II. Circuit Analysis-II Lecture # 5 Monday 23 rd April, 18
Circuit Analysis-II Capacitors in AC Circuits Introduction ü The instantaneous capacitor current is equal to the capacitance times the instantaneous rate of change of the voltage across the capacitor.
More informationEM Oscillations. David J. Starling Penn State Hazleton PHYS 212
I ve got an oscillating fan at my house. The fan goes back and forth. It looks like the fan is saying No. So I like to ask it questions that a fan would say no to. Do you keep my hair in place? Do you
More informationImpedance/Reactance Problems
Impedance/Reactance Problems. Consider the circuit below. An AC sinusoidal voltage of amplitude V and frequency ω is applied to the three capacitors, each of the same capacitance C. What is the total reactance
More informationCourse Updates. Reminders: 1) Assignment #10 due Today. 2) Quiz # 5 Friday (Chap 29, 30) 3) Start AC Circuits
ourse Updates http://www.phys.hawaii.edu/~varner/phys272-spr10/physics272.html eminders: 1) Assignment #10 due Today 2) Quiz # 5 Friday (hap 29, 30) 3) Start A ircuits Alternating urrents (hap 31) In this
More information21 MAGNETIC FORCES AND MAGNETIC FIELDS
CHAPTER 1 MAGNETIC FORCES AND MAGNETIC FIELDS ANSWERS TO FOCUS ON CONCEPTS QUESTIONS 1 (d) Right-Hand Rule No 1 gives the direction of the magnetic force as x for both drawings A and B In drawing C, the
More informationPHYS 202 Notes, Week 6
PHYS 202 Notes, Week 6 Greg Christian February 23 & 25, 2016 Last updated: 02/25/2016 at 12:36:40 This week we learn about electromagnetic induction. Magnetic Induction This section deals with magnetic
More informationFaraday s Law; Inductance
This test covers Faraday s Law of induction, motional emf, Lenz s law, induced emf and electric fields, eddy currents, self-inductance, inductance, RL circuits, and energy in a magnetic field, with some
More informationExam 2 Solutions. Note that there are several variations of some problems, indicated by choices in parentheses.
Exam 2 Solutions Note that there are several variations of some problems, indicated by choices in parentheses. Problem 1 Part of a long, straight insulated wire carrying current i is bent into a circular
More informationPhysics 1302W.400 Lecture 33 Introductory Physics for Scientists and Engineering II
Physics 1302W.400 Lecture 33 Introductory Physics for Scientists and Engineering II In today s lecture, we will discuss generators and motors. Slide 30-1 Announcement Quiz 4 will be next week. The Final
More informationChapter 21: RLC Circuits. PHY2054: Chapter 21 1
Chapter 21: RC Circuits PHY2054: Chapter 21 1 Voltage and Current in RC Circuits AC emf source: driving frequency f ε = ε sinωt ω = 2π f m If circuit contains only R + emf source, current is simple ε ε
More informationYell if you have any questions
Class 36: Outline Hour 1: Concept Review / Overview PRS Questions Possible Exam Questions Hour : Sample Exam Yell if you have any questions P36-1 Before Starting All of your grades should now be posted
More informationUniversity Physics 227N/232N Ch 27: Inductors, towards Ch 28: AC Circuits Quiz and Homework Due This Week Exam Next Wednesday!
Vector pointing OUT of page University Physics 227N/232N Ch 27: Inductors, towards Ch 28: AC Circuits Quiz and Homework Due This Week Exam Next Wednesday! (April 9) Dr. Todd Satogata (ODU/Jefferson Lab)
More informationChapters 34,36: Electromagnetic Induction. PHY2061: Chapter
Chapters 34,36: Electromagnetic Induction PHY2061: Chapter 34-35 1 Electromagnetic Induction Magnetic flux Induced emf Faraday s Law Lenz s Law Motional emf Magnetic energy Inductance RL circuits Generators
More informationFINAL EXAM - Physics Patel SPRING 1998 FORM CODE - A
FINAL EXAM - Physics 202 - Patel SPRING 1998 FORM CODE - A Be sure to fill in your student number and FORM letter (A, B, C, D, E) on your answer sheet. If you forget to include this information, your Exam
More informationSCHOOL OF MATHEMATICS MATHEMATICS FOR PART I ENGINEERING. Self-paced Course
SCHOOL OF MATHEMATICS MATHEMATICS FOR PART I ENGINEERING Self-paced Course MODULE 26 APPLICATIONS TO ELECTRICAL CIRCUITS Module Topics 1. Complex numbers and alternating currents 2. Complex impedance 3.
More informationLecture 13.2 :! Inductors
Lecture 13.2 :! Inductors Lecture Outline:! Induced Fields! Inductors! LC Circuits! LR Circuits!! Textbook Reading:! Ch. 33.6-33.10 April 9, 2015 1 Announcements! HW #10 due on Tuesday, April 14, at 9am.!
More information(a) What is the direction of the magnetic field at point P (i.e., into or out of the page), and why?
Physics 9 Fall 2010 Midterm 2 s For the midterm, you may use one sheet of notes with whatever you want to put on it, front and back Please sit every other seat, and please don t cheat! If something isn
More informationInduction_P1. 1. [1 mark]
Induction_P1 1. [1 mark] Two identical circular coils are placed one below the other so that their planes are both horizontal. The top coil is connected to a cell and a switch. The switch is closed and
More informationPhysics 115. AC: RL vs RC circuits Phase relationships RLC circuits. General Physics II. Session 33
Session 33 Physics 115 General Physics II AC: RL vs RC circuits Phase relationships RLC circuits R. J. Wilkes Email: phy115a@u.washington.edu Home page: http://courses.washington.edu/phy115a/ 6/2/14 1
More informationElectromagnetic Induction & Inductors
Electromagnetic Induction & Inductors 1 Revision of Electromagnetic Induction and Inductors (Much of this material has come from Electrical & Electronic Principles & Technology by John Bird) Magnetic Field
More informationVersion 001 HW 22 EM Induction C&J sizemore (21301jtsizemore) 1
Version 001 HW 22 EM Induction C&J sizemore (21301jtsizemore) 1 This print-out should have 35 questions. Multiple-choice questions may continue on the next column or page find all choices before answering.
More informationMagnetic Fields Part 3: Electromagnetic Induction
Magnetic Fields Part 3: Electromagnetic Induction Last modified: 15/12/2017 Contents Links Electromagnetic Induction Induced EMF Induced Current Induction & Magnetic Flux Magnetic Flux Change in Flux Faraday
More informationChapter 30. Inductance
Chapter 30 Inductance Self Inductance When a time dependent current passes through a coil, a changing magnetic flux is produced inside the coil and this in turn induces an emf in that same coil. This induced
More informationALI RAZA KAMAL EXERCISE NOTES
ALI RAZA KAMAL EXERCISE NOTES Physics 2 nd Year Ali Raza Electrostatics 2 QUESTIONS 2.. The potential is constant throughout a given region of space. Is the electric field is zero or non-zero in this region?
More informationUnit-14 Electromagnetic Induction and Alternating Current
Unit-4 Electromagnetic Induction and Alternating Current 73 SUMMEY. Net flux through the surface BdA = BA cos = angle between area vector A if = 0 then max = BA if = 90 then = 0 & magnetic field B. Unit
More informationInduction and Inductance
Induction and Inductance Key Contents Faraday s law: induced emf Induction and energy transfer Inductors and inductance RL circuits Magnetic energy density The First Experiment 1. A current appears only
More informationAC Circuits and Electromagnetic Waves
AC Circuits and Electromagnetic Waves Physics 102 Lecture 5 7 March 2002 MIDTERM Wednesday, March 13, 7:30-9:00 pm, this room Material: through next week AC circuits Next week: no lecture, no labs, no
More informationElectromagnetic Induction and Waves (Chapters 33-34)
Electromagnetic nduction and Waves (Chapters 33-34) The laws of emf induction: Faraday s and Lenz s laws Concepts of classical electromagnetism. Maxwell equations nductance Mutual inductance M Self inductance
More informationElectricity & Magnetism
Ch 31 Faraday s Law Electricity & Magnetism Up to this point, we ve seen electric fields produced by electric charges... E =... and magnetic fields produced by moving charges... k dq E da = q in r 2 B
More informationReview of Basic Electrical and Magnetic Circuit Concepts EE
Review of Basic Electrical and Magnetic Circuit Concepts EE 442-642 Sinusoidal Linear Circuits: Instantaneous voltage, current and power, rms values Average (real) power, reactive power, apparent power,
More informationUniversity of the Philippines College of Science PHYSICS 72. Summer Second Long Problem Set
University of the Philippines College of Science PHYSICS 72 Summer 2012-2013 Second Long Problem Set INSTRUCTIONS: Choose the best answer and shade the corresponding circle on your answer sheet. To change
More informationChapter 23: Magnetic Flux and Faraday s Law of Induction
Chapter 3: Magnetic Flux and Faraday s Law of Induction Answers Conceptual Questions 6. Nothing. In this case, the break prevents a current from circulating around the ring. This, in turn, prevents the
More informationChapter 1 Magnetic Circuits
Principles of Electric Machines and Power Electronics Third Edition P. C. Sen Chapter 1 Magnetic Circuits Chapter 1: Main contents i-h relation, B-H relation Magnetic circuit and analysis Property of magnetic
More information