21 MAGNETIC FORCES AND MAGNETIC FIELDS
|
|
- Susanna Floyd
- 5 years ago
- Views:
Transcription
1 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 velocity is parallel to the magnetic field, so the magnetic force is zero (b) Using Right-Hand Rule No 1 (see Section 1), we find that the direction of the magnetic force on a positively charged particle is to the west Reversing this direction because the particle is a negative electron, we see that the magnetic force acting on it points to the east 3 (a) Using Right-Hand Rule No 1 (see Section 1), we find that the direction of the magnetic force on a positively charged particle is straight down toward the bottom of the screen 4 B = T, south 5 (c) The electric force points out of the screen, in the direction of the electric field An application of Right- Hand Rule No 1 shows that the magnetic force also points out of the screen, parallel to the electric force When two forces have the same direction, the magnitude of their sum has the largest possible value 6 (e) In this situation, the centripetal force, F c = mv /r (Equation 53), is provided by the magnetic force, F = qvb sin 900 (Equation 11), so mv /r = qvb sin 900 Thus, q mv / rb, and the charge magnitude q is inversely proportional to the radius r Since the radius of curve 1 is smaller than that of curve, and the radius of curve is smaller than that of curve 3, we conclude that q 1 is larger than q, which is larger than q 3 7 (a) The magnetic force that acts on the electron in regions 1 and is always perpendicular to its path, so the force does no work According to the work-energy theorem, Equation 63, the kinetic energy, and hence speed, of the electron does not change when no work is done 8 (d) According to Equation 1, the radius r of the circular path is given by r mv / qb Since v, q, and B are the same for the proton and the electron, the more-massive proton travels on the circle with the greater radius The centripetal force F c acting on the proton must point toward the center of the circle In this case, the centripetal force is provided by the magnetic force F According to Right-Hand Rule No 1, the direction of F is related to the velocity v and the magnetic field B An application of this rule shows that the proton must travel counterclockwise around the circle in order that the magnetic force point toward the center of the circle 9 r proton /r electron = (c) When, for example, a particle moves perpendicular to a magnetic field, the field exerts a force that causes the particle to move on a circular path Any object moving on a circular path experiences a centripetal acceleration 11 F = 30 N, along the y axis
2 1 (e) The magnetic field is directed from the north pole to the south pole (Section 11) According to Right- Hand Rule No 1 (Section 15), the magnetic force in drawing 1 points north 13 (c) There is no net force No force is exerted on the top and bottom wires, because the current is either in the same or opposite direction as the magnetic field According to Right-Hand Rule No 1 (Section 15), the left side of the loop experiences a force that is directed into the screen, and the right side experiences a force that is directed out of the screen (toward the reader) The two forces have the same magnitude, so the net force is zero The two forces on the left and right sides, however, do exert a net torque on the loop with respect to the axis 14 (d) According to Right-Hand Rule No 1 (Section 15), all four sides of the loop are subject to forces that are directed perpendicularly toward the opposite side of the square In addition, the forces have the same magnitude, so the net force is zero A torque consists of a force and a lever arm For the axis of rotation through the center of the loop, the lever arm for each of the four forces is zero, so the net torque is also zero 15 N = 86 turns 16 (a) Right-Hand Rule No (Section 17) indicates that the magnetic field from the top wire in points into the screen and that from the bottom wire points out of the screen Thus, the net magnetic field in is zero Also, the magnetic field from the horizontal wire in 4 points into the screen and that from the vertical wire points out of the screen Thus, the net magnetic field in 4 is also zero 17 (b) Two wires attract each other when the currents are in the same direction and repel each other when the currents are in the opposite direction (see Section 17) Wire B is attracted to A and repelled by C, but the forces reinforce one another Therefore, the net force has a magnitude of F BA + F BC, where F BA and F BC are the magnitudes of the forces exerted on wire B by A and on wire B by C However, F BA = F BC, since the wires A and C are equidistance from B Therefore, the net force on wire B has a magnitude of F BA The net force exerted on wire A is less than this, because wire A is attracted to B and repelled by C, the forces partially canceling The net force expected on wire C is also less than that on A It is repelled by both A and B, but A is twice as far away as B 18 (a) The magnetic field in the region inside a solenoid is constant, both in magnitude and in direction (see Section 17) 19 B = T, out of the screen 0 (d) According to Ampere s law, I is the net current passing through the surface bounded by the path The net current is 3 A + 4 A 5 A = A
3 CHAPTER ELECTROMAGNETIC INDUCTION ANSWERS TO FOCUS ON CONCEPTS QUESTIONS 1 35 m/s (e) The work done by the hand equals the energy dissipated in the bulb The energy dissipated in the bulb equals the power used by the bulb times the time Since the time is the same in each case, more work is done when the power used is greater The power, however, is the voltage squared divided by the resistance of the bulb, according to Equation 06c, so that a smaller resistance corresponds to a greater power Thus, more work is done when the resistance of the bulb is smaller 3 (c) The magnetic flux Ф that passes through a surface is BAcos (Equation ), where B is the magnitude of the magnetic field, A is the area of the surface, and is the angle between the field and the normal to the surface Knowing Ф and A, we can calculate Bcos / A, which is the component of the field parallel to the normal or perpendicular to the surface 4 (b) The magnetic flux Ф that passes through a surface is BAcos (Equation ), where B is the magnitude of the magnetic field, A is the area of the surface, and is the angle between the field and the normal to the surface It has the greatest value when the field strikes the surface perpendicularly 0 and a value of zero when the field is parallel to a surface 90 The field is more nearly perpendicular to face 1 0 than to face 3 70 and is parallel to face 5 (d) Faraday s law of electromagnetic induction states that the average emf induced in a coil of N loops is N / t (Equation 3), where Ф is the change in magnetic flux through one loop and t is the time interval during which the change occurs Reducing the time interval t during which the field magnitude increases means that the rate of change of the flux will increase, which will increase (not reduce) the induced emf 6 3 V 7 (c) According to Faraday s law, the magnitude of the induced emf is the magnitude of the change in magnetic flux divided by the time interval over which the change occurs (see Equation 3) In each case the field is perpendicular to the coil, and the initial flux is zero since the coil is outside the field region Therefore, the changes in flux are as follows: BL, BL (see Equation ) The A B C corresponding time intervals are ta tb t, tc t Dividing gives the following results for the magnitudes of the emfs: A BL, B L B, B L BL C t t t t 8 (a) An induced current appears only when there is an induced emf to drive it around the loop According to Faraday s law, an induced emf exists only when the magnetic flux through the loop changes as time passes Here, however, there is no magnetic flux through the loop The magnetic field lines produced by the current are circular and centered on the wire, with the planes of the circles perpendicular to the wire Therefore, the magnetic field is always parallel to the plane of the loop as the loop falls and never penetrates the loop In
4 other words, no magnetic flux passes through the loop No magnetic flux, no induced emf, no induced current 9 (d) When the switch is closed, current begins to flow counterclockwise in the larger coil, and the field that it creates appears inside the smaller coil Using RHR- reveals that this field points out of the screen toward you According to Lenz s law, the induced current in the smaller coil flows in such a direction that it creates an induced field that opposes the growth of the field from the larger coil Thus, the induced field must point into the screen away from you Using RHR- reveals that the induced current must, then, flow clockwise The induced current exists only for the short period following the closing of the switch, when the field from the larger coil is growing from zero to its equilibrium value Once the field from the larger coil reaches its equilibrium value and ceases to change, the induced current in the smaller coil becomes zero 10 (b) The peak emf is proportional to the area A of the coil, according to Equation 4 Thus, we need to consider the areas of the coils The length of the wire is L and is the same for each of the coil shapes For the circle, the circumference is πr = L, so that the area is the area is A square A circle L L r For the square, 4 L L For the rectangle, the perimeter is (D + D) = L, so that the area is 4 16 L L L Arectangle The circle has the largest area, while the rectangle has the smallest area, corresponding to answer b cm 1 (d) The back emf is proportional to the motor speed, so it decreases when the speed decreases The current V I drawn by the motor is given by Equation 5 as I, where V is the voltage at the socket, is the R back emf, and R is the resistance of the motor coil As decreases, I increases 13 (c) According to Equation 7, the mutual inductance is St M If the time interval is cut in half and I the change in the primary current is doubled, while the induced emf remains the same, the mutual inductance must be reduced by a factor of four 14 (b) The energy stored in an inductor is given by Equation 10 as inductors store the same amount of energy, we have I1 L L 1414 I L L / 1 15 (e) According to Equation 8, we have 1 1 L1 I 1 L I P Energy Thus, 1 LI Since the two LI N Since Ф is the same for each coil, the number of turns is proportional to the product LI of the inductance and the current For the coils specified in the table, this product is (LI) A = L 0, (LI) B = L 0 /, (LI) C = 4L 0 16 (c) The current in the primary is proportional to the current in the secondary according to Equation 13: I I N / N The current in the secondary is the secondary voltage divided by the resistance, according P S S P to Ohm s law Thus, when the resistance increases, the current in the secondary decreases and so does the
5 current in the primary The wall socket delivers to the primary the same power that the secondary delivers to the resistance, assuming that no power is lost within the transformer The power delivered to the resistance is given by Equation 015c as the square of the secondary voltage divided by the resistance When the resistance increases, the power decreases Hence, the power delivered to the primary by the wall socket also decreases W 18 (a) The current in resistor (without the transformer) is the same as the current in resistor 1 (with the transformer) In either event, the current I is I = V/R, where V is the voltage across the resistance R Since the transformer is a step-up transformer, the voltage applied across resistor is smaller than the voltage applied across resistor 1 The smaller voltage across resistor can lead to the same current as does the greater voltage across resistor 1 only if R is less than R 1
Physics 6B Summer 2007 Final
Physics 6B Summer 2007 Final Question 1 An electron passes through two rectangular regions that contain uniform magnetic fields, B 1 and B 2. The field B 1 is stronger than the field B 2. Each field fills
More informationLenz s Law (Section 22.5)
Lenz s Law (Section 22.5) : Thursday, 25 of February 7:00 9:00 pm Rooms: Last Name Room (Armes) Seats A - F 201 122 G - R 200 221 S - Z 205 128 2016-02-21 Phys 1030 General Physics II (Gericke) 1 1) Charging
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 informationMagnetism. and its applications
Magnetism and its applications Laws of Magnetism 1) Like magnetic poles repel, and 2) unlike poles attract. Magnetic Direction and Strength Law 3 - Magnetic force, either attractive or repelling varies
More informationFARADAY S AND LENZ LAW B O O K P G
FARADAY S AND LENZ LAW B O O K P G. 4 3 6-438 MOTIONAL EMF AND MAGNETIC FLUX (DERIVIATION) Motional emf = vbl Let a conducting rod being moved through a magnetic field B During time t 0 the rod has been
More informationLECTURE 22 MAGNETIC TORQUE & MAGNETIC FIELDS. Instructor: Kazumi Tolich
LECTURE 22 MAGNETIC TORQUE & MAGNETIC FIELDS Instructor: Kazumi Tolich Lecture 22 2! Reading chapter 22.5 to 22.7! Magnetic torque on current loops! Magnetic field due to current! Ampere s law! Current
More informationChapter 27, 28 & 29: Magnetism & Electromagnetic Induction. Magnetic flux Faraday s and Lenz s law Electromagnetic Induction Ampere s law
Chapter 27, 28 & 29: Magnetism & Electromagnetic Induction Magnetic flux Faraday s and Lenz s law Electromagnetic Induction Ampere s law 1 Magnetic Flux and Faraday s Law of Electromagnetic Induction We
More informationChapter 12. Magnetism and Electromagnetism
Chapter 12 Magnetism and Electromagnetism 167 168 AP Physics Multiple Choice Practice Magnetism and Electromagnetism SECTION A Magnetostatics 1. Four infinitely long wires are arranged as shown in the
More informationPS I AP Physics 2 Electromagnetic Induction Multiple Choice Questions
PS I AP Physics 2 Electromagnetic Induction Multiple Choice Questions 1. A beam of electrons travels between two parallel coils of wire, as shown in the figures above. When the coils do not carry a current,
More informationUnit 8: Electromagnetism
Multiple Choice Portion Unit 8: Electromagnetism 1. Four compasses are placed around a conductor carrying a current into the page, as shown below. Which compass correctly shows the direction of the magnetic
More informationMagnetic Fields & Forces
Magnetic Fields & Forces Oersted discovered that an electric current will produce a magnetic field around conductor only a moving charge creates a magnetic field the magnetic field is circular around the
More informationElectrics. Electromagnetism
Electrics Electromagnetism Electromagnetism Magnetism is associated with charges in motion (currents): microscopic currents in the atoms of magnetic materials. macroscopic currents in the windings of an
More informationPHY 131 Review Session Fall 2015 PART 1:
PHY 131 Review Session Fall 2015 PART 1: 1. Consider the electric field from a point charge. As you move farther away from the point charge, the electric field decreases at a rate of 1/r 2 with r being
More informationCh 17 Problem Set 31. A toaster is rated at 600 W when connected to a 120-V source. What current does the toaster carry, and what is its resistance?
Ch 17 Problem Set 31. A toaster is rated at 600 W when connected to a 120-V source. What current does the toaster carry, and what is its resistance? 33. How many 100-W lightbulbs can you use in a 120-V
More informationREVIEW SESSION. Midterm 2
REVIEW SESSION Midterm 2 Summary of Chapter 20 Magnets have north and south poles Like poles repel, unlike attract Unit of magnetic field: tesla Electric currents produce magnetic fields A magnetic field
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 information1. An isolated stationary point charge produces around it. a) An electric field only. b) A magnetic field only. c) Electric as well magnetic fields.
1. An isolated stationary point charge produces around it. a) An electric field only. b) A magnetic field only. c) Electric as well magnetic fields. 2. An isolated moving point charge produces around it.
More informationAP Physics 2 Electromagnetic Induction Multiple Choice
Slide 1 / 50 AP Physics 2 Electromagnetic Induction Multiple Choice www.njctl.org Slide 2 / 50 1 A beam of electrons travels between two parallel coils of wire, as shown in the figures above. When the
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 informationVersion The diagram below represents lines of magnetic flux within a region of space.
1. The diagram below represents lines of magnetic flux within a region of space. 5. The diagram below shows an electromagnet made from a nail, a coil of insulated wire, and a battery. The magnetic field
More informationa) head-on view b) side view c) side view Use the right hand rule for forces to confirm the direction of the force in each case.
Electromagnetism Magnetic Force on a Wire Magnetic Field around a Bar Magnet Direction of magnetic field lines: the direction that the North pole of a small test compass would point if placed in the field
More informationMagnetic Fields & Forces
Magnetic Fields & Forces Oersted discovered that an electric current will produce a magnetic field around conductor only a moving charge creates a magnetic field the magnetic field is circular around the
More informationElectromagnetism IB 12
Electromagnetism Magnetic Field around a Bar Magnet Direction of magnetic field lines: the direction that the North pole of a small test compass would point if placed in the field (N to S) What is the
More informationPH202-NG Test 2 (July. 7, 2009, 3:00PM-5:05PM)
name Write your name also in the back of the last page. blazer id [a] PH202-NG Test 2 (July. 7, 2009, 3:00PM-5:05PM) You may not open the textbook nor notebook. A letter size information may be used. A
More informationP202 Practice Exam 2 Spring 2004 Instructor: Prof. Sinova
P202 Practice Exam 2 Spring 2004 Instructor: Prof. Sinova Name: Date: (5)1. How many electrons flow through a battery that delivers a current of 3.0 A for 12 s? A) 4 B) 36 C) 4.8 10 15 D) 6.4 10 18 E)
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 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 informationFaraday's Law ds B B G G ΦB B ds Φ ε = d B dt
Faraday's Law ds ds ε= d Φ dt Φ Global Review Electrostatics» motion of q in external E-field» E-field generated by Σq i Magnetostatics» motion of q and i in external -field» -field generated by I Electrodynamics»
More informationHW7: Ch. 26 P 34, 36 Ch.27 Q 2, 4, 8, 18 P 2, 8, 17, 19, 37
Fall 12 PHY 122 Homework Solutions #7 HW7: Ch. 26 P 34, 36 Ch.27 Q 2, 4, 8, 18 P 2, 8, 17, 19, 37 Chapter 26 Problem 34 Determine the magnitudes and directions of the currents in each resistor shown in
More informationGeneral Physics (PHY 2140)
General Physics (PHY 2140) Lecture 15 Electricity and Magnetism Magnetism Applications of magnetic forces Induced voltages and induction Magnetic flux and induced emf Faraday s law http://www.physics.wayne.edu/~apetrov/phy2140/
More information3/31/2014. Resistors in series. Resistors in parallel. Ohm s Law. Review for Test 2. Electric Power (cont d) V IR. R constant I
Ohm s Law eview for Test Ohm s law states that the current flowing through a piece of material is proportional to the voltage applied across the material. The resistance () is defined as the ratio of to.
More informationAP Physics Electromagnetic Wrap Up
AP Physics Electromagnetic Wrap Up Here are the glorious equations for this wonderful section. This is the equation for the magnetic force acting on a moving charged particle in a magnetic field. The angle
More informationPHYSICS 3204 PUBLIC EXAM QUESTIONS (Magnetism &Electromagnetism)
PHYSICS 3204 PUBLIC EXAM QUESTIONS (Magnetism &Electromagnetism) NAME: August 2009---------------------------------------------------------------------------------------------------------------------------------
More informationInduction and Inductance
Welcome Back to Physics 1308 Induction and Inductance Michael Faraday 22 September 1791 25 August 1867 Announcements Assignments for Tuesday, November 6th: - Reading: Chapter 30.6-30.8 - Watch Videos:
More informationweek 8 The Magnetic Field
week 8 The Magnetic Field General Principles General Principles Applications Start with magnetic forces on moving charges and currents A positive charge enters a uniform magnetic field as shown. What is
More informationPhysics / Higher Physics 1A. Electricity and Magnetism Revision
Physics / Higher Physics 1A Electricity and Magnetism Revision Electric Charges Two kinds of electric charges Called positive and negative Like charges repel Unlike charges attract Coulomb s Law In vector
More informationMagnetism is associated with charges in motion (currents):
Electrics Electromagnetism Electromagnetism Magnetism is associated with charges in motion (currents): microscopic currents in the atoms of magnetic materials. macroscopic currents in the windings of an
More informationPHYS 1444 Section 02 Review #2
PHYS 1444 Section 02 Review #2 November 9, 2011 Ian Howley 1 1444 Test 2 Eq. Sheet Terminal voltage Resistors in series Resistors in parallel Magnetic field from long straight wire Ampére s Law Force on
More informationChapter 27, 28 & 29: Magnetism & Electromagnetic Induction
Chapter 27, 28 & 29: Magnetism & Electromagnetic Induction The Magnetic Field The Magnetic Force on Moving Charges The Motion of Charged Particles in a Magnetic Field The Magnetic Force Exerted on a Current-Carrying
More informationChapter 23 Magnetic Flux and Faraday s Law of Induction
Chapter 23 Magnetic Flux and Faraday s Law of Induction Recall: right hand rule 2 10/28/2013 Units of Chapter 23 Induced Electromotive Force Magnetic Flux Faraday s Law of Induction Lenz s Law Mechanical
More informationName: Class: Date: AP Physics Spring 2012 Q6 Practice. Multiple Choice Identify the choice that best completes the statement or answers the question.
ame: Class: Date: ID: A AP Physics Spring 2012 Q6 Practice Multiple Choice Identify the choice that best completes the statement or answers the question. 1. (2 points) A potential difference of 115 V across
More informationPhysics 106, Section 1
Physics 106, Section 1 Magleby Exam 2, Summer 2012 Exam Cid You are allowed a pencil and a testing center calculator. No scratch paper is allowed. Testing center calculators only. 1. A circular coil lays
More informationQuestion 6.1: Predict the direction of induced current in the situations described by the following Figs. 6.18(a) to (f ). (a) (b) (c) (d) (e) (f) The direction of the induced current in a closed loop
More informationGeneral Physics II. Magnetism
General Physics II Magnetism Bar magnet... two poles: N and S Like poles repel; Unlike poles attract. Bar Magnet Magnetic Field lines [B]: (defined in a similar way as electric field lines, direction and
More informationSolutions to PHY2049 Exam 2 (Nov. 3, 2017)
Solutions to PHY2049 Exam 2 (Nov. 3, 207) Problem : In figure a, both batteries have emf E =.2 V and the external resistance R is a variable resistor. Figure b gives the electric potentials V between the
More informationSolution for Fq. A. up B. down C. east D. west E. south
Solution for Fq A proton traveling due north enters a region that contains both a magnetic field and an electric field. The electric field lines point due west. It is observed that the proton continues
More informationCollege Physics B - PHY2054C
Force on a Torque on a College - PHY2054C & 09/29/2014 My Office Hours: Tuesday 10:00 AM - Noon 206 Keen Building Outline Force on a Torque on a 1 Force on a Torque on a 2 3 4 Force on a Torque on a Force
More informationChapter 30. Induction and Inductance
Chapter 30 Induction and Inductance 30.2: First Experiment: 1. A current appears only if there is relative motion between the loop and the magnet (one must move relative to the other); the current disappears
More informationPHYS 241 EXAM #2 November 9, 2006
1. ( 5 points) A resistance R and a 3.9 H inductance are in series across a 60 Hz AC voltage. The voltage across the resistor is 23 V and the voltage across the inductor is 35 V. Assume that all voltages
More informationChapter 5: Electromagnetic Induction
Chapter 5: Electromagnetic Induction 5.1 Magnetic Flux 5.1.1 Define and use magnetic flux Magnetic flux is defined as the scalar product between the magnetic flux density, B with the vector of the area,
More information1. Write the relation for the force acting on a charge carrier q moving with velocity through a magnetic field in vector notation. Using this relation, deduce the conditions under which this force will
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 informationMagnets and Electromagnetism
Review 9 Magnets and Electromagnetism 1. A 1.2 cm wire carrying a current of 0.8 A is perpendicular to a 2.4 T magnetic field. What is the magnitude of the force on the wire? 2. A 24 cm length of wire
More informationGravity Electromagnetism Weak Strong
19. Magnetism 19.1. Magnets 19.1.1. Considering the typical bar magnet we can investigate the notion of poles and how they apply to magnets. 19.1.1.1. Every magnet has two distinct poles. 19.1.1.1.1. N
More informationExam 2 Solutions. PHY2054 Spring Prof. Paul Avery Prof. Pradeep Kumar Mar. 18, 2014
Exam 2 Solutions Prof. Paul Avery Prof. Pradeep Kumar Mar. 18, 2014 1. A series circuit consists of an open switch, a 6.0 Ω resistor, an uncharged 4.0 µf capacitor and a battery with emf 15.0 V and internal
More informationChapter 30. Induction and Inductance
Chapter 30 Induction and Inductance 30.2: First Experiment: 1. A current appears only if there is relative motion between the loop and the magnet (one must move relative to the other); the current disappears
More informationDO PHYSICS ONLINE MOTORS AND GENERATORS FARADAY S LAW ELECTROMAGNETIC INDUCTION
DO PHYSICS ONLINE MOTORS AND GENERATORS FARADAY S LAW ELECTROMAGNETIC INDUCTION English Michael Faraday (1791 1867) who experimented with electric and magnetic phenomena discovered that a changing magnetic
More information$ B 2 & ) = T
Solutions PHYS 251 Final Exam Practice Test 1D If we find the resultant velocity, v, its vector is 13 m/s. This can be plugged into the equation for magnetic force: F = qvb = 1.04 x 10-17 N, where q is
More informationExam 2 Solutions. Answer: 3.0 W Solution: The total current is in the series circuit is 1 A, so the power dissipated in R 2 is i 2 R 2
Exam 2 Solutions Prof. Pradeep Kumar Prof. Paul Avery Mar. 21, 2012 1. A portable CD player does not have a power rating listed, but it has a label stating that it draws a maximum current of 159.0 ma.
More informationUniversity Physics (Prof. David Flory) Chapt_29 Sunday, February 03, 2008 Page 1
University Physics (Prof. David Flory) Chapt_29 Sunday, February 03, 2008 Page 1 Name: Date: 1. A loop of current-carrying wire has a magnetic dipole moment of 5 10 4 A m 2. The moment initially is aligned
More informationa. Clockwise. b. Counterclockwise. c. Out of the board. d. Into the board. e. There will be no current induced in the wire
Physics 1B Winter 2012: Final Exam For Practice Version A 1 Closed book. No work needs to be shown for multiple-choice questions. The first 10 questions are the makeup Quiz. The remaining questions are
More information8. (6) Consider the circuit here with resistors R A, R B and R C. Rank the
General Physics II Exam 2 - Chs. 18B 21 - Circuits, Magnetism, EM Induction - Oct. 3, 2013 Name Rec. Instr. Rec. Time For full credit, make your work clear. Show formulas used, essential steps, and results
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 informationSECTION A Magnetostatics
P Physics Multiple hoice Practice Magnetism and lectromagnetism NSWRS STION Magnetostatics Solution For the purposes of this solution guide. The following hand rules will be referred to. RHR means right
More information22 ELECTROMAGNETIC INDUCTION
CHAPTER ELECTROMAGNETIC INDUCTION ANSWERS TO FOCUS ON CONCEPTS QUESTIONS. 3.5 m/s. (e) The work done by the hand equals the energy dissiated in the bulb. The energy dissiated in the bulb equals the ower
More informationPHY 114 Summer Midterm 2 Solutions
PHY 114 Summer 009 - Midterm Solutions Conceptual Question 1: Can an electric or a magnetic field, each constant in space and time, e used to accomplish the actions descried elow? Explain your answers.
More informationPhysics 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
More informationChapter 22, Magnetism. Magnets
Chapter 22, Magnetism Magnets Poles of a magnet (north and south ) are the ends where objects are most strongly attracted. Like poles repel each other and unlike poles attract each other Magnetic poles
More informationPhysics Week 5(Sem. 2) Name. Magnetism. Chapter Summary. Magnetic Fields
Physics Week 5(Sem. 2) Name Chapter Summary Magnetism Magnetic Fields Permanent magnets have long been used in navigational compasses. The needle in a compass is supported to allow it to freely rotate
More informationExam II. Solutions. Part A. Multiple choice questions. Check the best answer. Each question carries a value of 4 points. The wires repel each other.
Exam II Solutions Part A. Multiple choice questions. Check the best answer. Each question carries a value of 4 points. 1.! Concerning electric and magnetic fields, which of the following is wrong?!! A
More informationPHYS 1102 EXAM - II. SECTION: (Circle one) 001 (TH 9:30 AM to 10:45AM) 002 (TH 3:30 PM to 4:45 PM) You have 1 hr 45 minutes to complete the test
PHYS 1102 EXAM - II SECTION: (Circle one) 001 (TH 9:30 AM to 10:45AM) 002 (TH 3:30 PM to 4:45 PM) Your Name: Student ID: You have 1 hr 45 minutes to complete the test PLEASE DO NOT START TILL YOU ARE INSTRUCTED
More informationPhysics of Everyday Phenomena. Chapter 14
Physics of Everyday Phenomena W. Thomas Griffith Juliet W. Brosing Chapter 14 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Question 14.1 With magnets A) like
More informationPHYSICS Fall Lecture 15. Electromagnetic Induction and Faraday s Law
PHYSICS 1444-001 Fall 2012 Lecture 15 Electromagnetic Induction and Faraday s Law A current can be produced by a changing magnetic field First shown in an experiment by Michael Faraday Induced emf A primary
More information= 8.89x10 9 N m 2 /C 2
PHY303L Useful Formulae for Test 2 Magnetic Force on a moving charged particle F B = q v B Magnetic Force on a current carrying wire F B = i L B Magnetic dipole moment µ = NiA Torque on a magnetic dipole:
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 informationChapter 5. Electromagnetic Induction
Chapter 5 Electromagnetic Induction Overview In the last chapter, we studied how a current produces a magnetic field. Here we will study the reverse effect: A magnetic field can produce an electric field
More informationChapter 9 FARADAY'S LAW Recommended Problems:
Chapter 9 FARADAY'S LAW Recommended Problems: 5,7,9,10,11,13,15,17,20,21,28,29,31,32,33,34,49,50,52,58,63,64. Faraday's Law of Induction We learned that e. current produces magnetic field. Now we want
More informationSECTION B Induction. 1. The rate of change of flux has which of the following units A) farads B) joules C) volts D) m/s E) webers
SECTION B Induction 1. The rate of change of flux has which of the following units ) farads B) joules C) volts D) m/s E) webers 2. For the solenoids shown in the diagram (which are assumed to be close
More informationPhysics 2220 Fall 2010 George Williams THIRD MIDTERM - REVIEW PROBLEMS
Physics 2220 Fall 2010 George Williams THIRD MIDTERM - REVIEW PROBLEMS Solution sets are available on the course web site. A data sheet is provided. Problems marked by "*" do not have solutions. 1. An
More informationPart 4: Electromagnetism. 4.1: Induction. A. Faraday's Law. The magnetic flux through a loop of wire is
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
More informationr where the electric constant
1.0 ELECTROSTATICS At the end of this topic, students will be able to: 10 1.1 Coulomb s law a) Explain the concepts of electrons, protons, charged objects, charged up, gaining charge, losing charge, charging
More informationC. Incorrect! Use the formula for magnetic flux. This is the product of magnetic field, times area, times the angle between them.
AP Physics - Problem Drill 17: Electromagnetism Instruction: (1) Read the problem statement and answer choices carefully (2) Work the problems on paper as 1. A house has a wall that has an area of 28 m
More informationTIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES. PHYS 1112, Exam 2 Section 1 Version 1 April 2, 2013 Total Weight: 100 points
TIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES PHYS 1112, Exam 2 Section 1 Version 1 April 2, 2013 Total Weight: 100 points 1. Check your examination for completeness prior to starting.
More informationThis Week. 1/22/2018 Physics 214 Summer
This Week Magnetism: Are you attracted or repelled? Where does magnetism come from? What use is magnetism? Post pictures and notes on refrigerators Electrical motors turn electricity into work Generators
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 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 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 informationPHYSICS 30 ELECTROMAGNETISM ASSIGNMENT 3 VERSION:0
Communication includes statement of the physics concept used and how it is applied in the situation along with diagrams, word explanations and calculations in a well laid out formula, substitution, answer
More informationRecap (1) Maxwell s Equations describe the electric field E and magnetic field B generated by stationary charge density ρ and current density J:
Class 13 : Induction Phenomenon of induction and Faraday s Law How does a generator and transformer work? Self- and mutual inductance Energy stored in B-field Recap (1) Maxwell s Equations describe the
More information4. An electron moving in the positive x direction experiences a magnetic force in the positive z direction. If B x
Magnetic Fields 3. A particle (q = 4.0 µc, m = 5.0 mg) moves in a uniform magnetic field with a velocity having a magnitude of 2.0 km/s and a direction that is 50 away from that of the magnetic field.
More informationExam III Solution: Chapters 18 20
PHYS 1420: College Physics II Fall 2006 Exam III Solution: Chapters 18 20 1. The anode of a battery A) has a positive charge, while the cathode has a negative charge. B) has a negative charge, while the
More informationGeneral Physics (PHY 2140)
General Physics (PHY 2140) Lecture 8 Electricity and Magnetism 1. Magnetism Application of magnetic forces Ampere s law 2. Induced voltages and induction Magnetic flux http://www.physics.wayne.edu/~alan/2140website/main.htm
More informationPhysics 54 Lecture March 1, Micro-quiz problems (magnetic fields and forces) Magnetic dipoles and their interaction with magnetic fields
Physics 54 Lecture March 1, 2012 OUTLINE Micro-quiz problems (magnetic fields and forces) Magnetic dipoles and their interaction with magnetic fields Electromagnetic induction Introduction to electromagnetic
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 informationElectromagnetic Induction Practice Problems Homework PSI AP Physics B
Electromagnetic Induction Practice Problems Homework PSI AP Physics B Name Multiple Choice Questions 1. A square loop of wire is placed in a uniform magnetic field perpendicular to the magnetic lines.
More informationMagnetic Fields; Sources of Magnetic Field
This test covers magnetic fields, magnetic forces on charged particles and current-carrying wires, the Hall effect, the Biot-Savart Law, Ampère s Law, and the magnetic fields of current-carrying loops
More informationUniversity Physics 227N/232N Ch 27: Inductors, towards Ch 28: AC Circuits Quiz and Homework This Week
Vector pointing OUT of page University Physics 227N/232N Ch 27: Inductors, towards Ch 28: AC Circuits Quiz and Homework This Week Dr. Todd Satogata (ODU/Jefferson Lab) satogata@jlab.org http://www.toddsatogata.net/2014-odu
More informationCHAPTER 4: MAGNETIC FIELD
CHAPTER 4: MAGNETIC FIELD PSPM II 2005/2006 NO. 4 4. FIGURE 3 A copper rod of mass 0.08 kg and length 0.20 m is attached to two thin current carrying wires, as shown in FIGURE 3. The rod is perpendicular
More informationAgenda for Today. Elements of Physics II. Forces on currents
Forces on currents Physics 132: Lecture e 14 Elements of Physics II Agenda for Today Currents are moving charges Torque on current loop Torque on rotated loop Currents create B-fields Adding magnetic fields
More information(D) Blv/R Counterclockwise
1. There is a counterclockwise current I in a circular loop of wire situated in an external magnetic field directed out of the page as shown above. The effect of the forces that act on this current is
More information