2015 Pearson Education, Inc. Section 24.5 Magnetic Fields Exert Forces on Moving Charges


 Albert Weaver
 2 years ago
 Views:
Transcription
1 Section 24.5 Magnetic Fields Exert Forces on Moving Charges
2 Magnetic Fields Sources of Magnetic Fields You already know that a moving charge is the creator of a magnetic field. Effects of Magnetic Fields If a moving charge experiences a magnetic field, it there will be a force on the charge. Sound familiar?!?!
3 Magnetic Fields Exert Forces on Moving Charges Magnetic fields also exert forces on moving charged particles and on electric currents in wires. There is no magnetic force on a charged particle at rest. There is no magnetic force on a charged particle moving parallel to a magnetic field. Slide 243
4 Magnetic Fields Exert Forces on Moving Charges As the angle α between the velocity and the magnetic field increases, the magnetic force also increases. The force is greatest when the angle is 90. The magnetic force is always perpendicular to the plane containing and. Slide 244
5 Magnetic Force on Particles A magnetic force is exerted on a particle within a magnetic field only if the particle has a charge. the charged particle is moving. with at least a portion of its velocity perpendicular to the magnetic field. Slide 245
6 Magnetic Force on a Charged Particle charge moving F B = magnitude: q: charge in Coulombs v: speed in meters/second B: magnetic field in Tesla Θ: angle between v and B vv qvb sinθ in a magnetic field with an angle not equal to 0 or 180 degrees direction: Right Hand Rule
7 Magnetic Fields Exert Forces on Moving Charges We determine the correct direction of the force using the righthand rule for forces. Slide 247
8 The right hand rule to determine magnetic force This right hand rule is a little different than what your book uses, but I think it s easier to remember. You must keep your hand in this configuration and turn your whole wrist!! F Point in the direction of the velocity. Turn your hand so that your middle finger (or three remaining fingers) point in the direction of the field. Your thumb gives you the direction of the force. v B Slide 248
9 Magnetic Fields Exert Forces on Moving Charges Slide 249
10 QuickCheck The direction of the magnetic force on the proton is A. To the right. B. To the left. C. Into the screen. D. Out of the screen. E. The magnetic force is zero. Slide 2410
11 QuickCheck The direction of the magnetic force on the proton is A. To the right. B. To the left. C. Into the screen. D. Out of the screen. E. The magnetic force is zero. Slide 2411
12 QuickCheck The diagram shows a top view of an electron beam passing between the poles of a magnet. The beam will be deflected A. Toward the north pole of the magnet. B. Toward the south pole of the magnet. C. Out of the plane of the figure D. Into the plane of the figure. Slide 2412
13 QuickCheck The diagram shows a top view of an electron beam passing between the poles of a magnet. The beam will be deflected A. Toward the north pole of the magnet. B. Toward the south pole of the magnet. C. Out of the plane of the figure D. Into the plane of the figure. Slide 2413
14 QuickCheck A beam of positively charged particles passes between the poles of a magnet as shown in the figure; the force on the particles is noted in the figure. The magnet s north pole is on the, the south pole on the. A. Left, right B. Right, left C. There s not enough information to tell. Slide 2414
15 QuickCheck A beam of positively charged particles passes between the poles of a magnet as shown in the figure; the force on the particles is noted in the figure. The magnet s north pole is on the, the south pole on the. A. Left, right B. Right, left C. There s not enough information to tell. Slide 2415
16 QuickCheck The direction of the magnetic force on the electron is A. Upward. B. Downward. C. Into the screen. D. Out of the screen. E. The magnetic force is zero. Slide 2416
17 QuickCheck The direction of the magnetic force on the electron is A. Upward. B. Downward. C. Into the screen. D. Out of the screen. E. The magnetic force is zero. Slide 2417
18 QuickCheck Which magnetic field causes the observed force? Slide 2418
19 QuickCheck Which magnetic field causes the observed force? C. Slide 2419
20 Sample Problem What is the magnetic force exerted on a 3.0 µc charge moving north at 300,000 m/s in a magnetic field of 200 mt if the field is directed a) North. b) South. c) East. d) West. Slide 2420
21 Sample Problem What is the magnetic force exerted on a 3.0 µc charge moving north at 300,000 m/s in a magnetic field of 200 mt if the field is directed a) North. b) South. c) East. d) West. F F F F F F B B B B B B = qvbsinθ = 6 3 ( 3 10 C)( 300,000 m/s)( T) sin( 0 ) = 0 = qvbsinθ = = F F F B B B = qvbsinθ = 6 3 ( 3 10 C)( 300,000 m/s)( T) sin( 180 ) = ( 3 10 C)( 300,000 m/s)( T) sin( 90 ) 0.18 N, down (toward Earth) F F F B B B = qvbsinθ = = 6 3 ( 3 10 C)( 300,000 m/s)( T) sin( 90 ) 0.18 N, up (toward sky)
22 Sample Problem Calculate the magnitude and direction of the magnetic force in the situation below. F F F B B B = qvbsinθ = 6 3 ( 3 10 C)( 300,000 m/s)( T) sin( 34 ) = N, out of the page
23 Conceptual Example 24.6 Determining the force on a moving electron An electron is moving to the right in a magnetic field that points upward, as in FIGURE What is the direction of the magnetic force? Slide 2423
24 Magnetic forces are always orthogonal (at right angles) to the plane established by the velocity and magnetic field vectors. can accelerate charged particles by changing their direction. can cause charged particles to move in circular or helical paths. Slide 2424
25 Magnetic forces cannot do work on charged particles. Why? The force is always perpendicular to the motion. What are the implications of this? They cannot change the speed or kinetic energy of charged particles. Slide 2425
26 This means magnetic forces are centripetal! Remember that centripetal acceleration is Therefore, centripetal force is v 2 a = c r mv 2 ΣF c = ma c = r Slide 2426
27 Paths of Charged Particles in Magnetic Fields When we studied the motion of objects subject to a force that was always perpendicular to the velocity, the result was circular motion at a constant speed. For example, a ball moved at the end of a string moved in a circle due to the perpendicular force of tension in the string. For a charged particle moving in a magnetic field, the magnetic force is always perpendicular to and so it causes the particle to move in a circle. Slide 2427
28 Paths of Charged Particles in Magnetic Fields A particle moving perpendicular to a uniform magnetic field undergoes uniform circular motion at constant speed. Slide 2428
29 Paths of Charged Particles in Magnetic Fields Derive an equation for the radius of orbit for a charged particle in a magnetic field. Slide 2429
30 Sample Problem What is the orbital radius of a proton moving at 20,000 m/s perpendicular to a 40 T magnetic field? Slide 2430
31 Sample Problem What is the orbital radius of a proton moving at 20,000 m/s perpendicular to a 40 T magnetic field? ma c = ΣF 2 v m = FB r 2 v m = qvbsinθ r v m = qbsinθ r mv r = = qbsinθ c 27 ( kg)( 20,000 m/s) 19 ( C)( 40 T) sin( 90 ) = m
32 Paths of Charged Particles in Magnetic Fields The motion of a charged particle when its velocity is neither parallel nor perpendicular to the magnetic field: Slide 2432
33 Paths of Charged Particles in Magnetic Fields Slide 2433
34 Paths of Charged Particles in Magnetic Fields Slide 2434
35 Paths of Charged Particles in Magnetic Fields Highenergy particles stream out from the sun in the solar wind, some of which becomes trapped in the earth s magnetic field. The particles spiral in helical trajectories along the earth s magnetic field lines. When they enter the atmosphere at the poles, they ionize gas, creating the aurora. Slide 2435
36 Sample Problem An electric field of 2000 N/C is directed to the south. A proton is traveling at 300,000 m/s to the west. What is the magnitude and direction of the force on the proton? Describe the path of the proton. Ignore gravitational effects. v F F F = qe = ( 19 )( N C 2000 ) = N C E The force is south. (Since the charge is positive, it will experience a force in the direction of the field.) Since the horizontal velocity is unchanged, the proton will follow a parabolic path downward. Slide 2436
37 Sample Problem A magnetic field of 2000 mt is directed to the south. A proton is traveling at 300,000 m/s to the west. What is the magnitude and direction of the force on the proton? Describe the path of the proton. Ignore gravitational effects. v F F F = qvbsinθ = 19 m 3 ( C)( 300,000 )( T) sin( 90 ) = N s The force is up (out of the page). (Since the charge is positive, use the right hand rule.) It will move in a circular path. B Slide 2437
38 Sample Problem How would you arrange a magnetic field and an electric field so that a charged particle of velocity v would pass straight through without deflection? Slide 2440
39 QuickCheck Which magnetic field (if it s the correct strength) allows the electron to pass through the charged electrodes without being deflected? Slide 2441
40 QuickCheck Which magnetic field (if it s the correct strength) allows the electron to pass through the charged electrodes without being deflected? E. Slide 2442
41 Electric and Magnetic Fields Together B e E This electron will experience an upward force from the electric field (opposite the direction of the field) and a downward force from the magnetic field (left hand rule). Slide 2443
42 Sample Problem It is found that protons traveling at 20,000 m/s pass undeflected through the velocity filter below. What is the magnitude and direction of the magnetic field between the plates? e 20,000 m/s 0.02 m 400 V Solution on next page. Slide 2444
43 Solution V = Ed Undeflected means that ΣF = 0. ΣF F e = qe = qvsinθ E = B vsinθ B = = 0 = F F B B F qe = qvbsinθ qvbsinθ qvsinθ N ( 20,000 C ) m ( 20,000 ) s e sin 90 = 1T, into the page E = V d = 400 V 0.02 m = 20,000 V m Slide 2445
44 Electromagnetic Flowmeters An electromagnetic flowmeter is a device that can be used to measure the blood flow in an artery. It applies a magnetic field across the artery, which separates the positive and negative ions in the blood. The flowmeter measures the potential difference due to the separation of the ions. The faster the blood s ions are moving, the greater the forces separating the ions become, therefore generating a higher voltage. Therefore, the measured voltage is proportional to the velocity of the blood. Slide 2446
45 Electromagnetic Flowmeters Slide 2447
46 Electromagnetic Flowmeters Slide 2448
47 Don t Try It Yourself: Magnets and Television Screens The image on a cathoderay tube television screen is drawn by an electron beam that is steered by magnetic fields from coils of wire. Other magnetic fields can also exert forces on the moving electrons. If you place a strong magnet near the TV screen, the electrons will be forced along altered trajectories and will strike different places on the screen than they are supposed to, producing an array of bright colors. (The magnet can magnetize internal components and permanently alter the image, so do not do this to your television!) Slide 2457
48 Section 24.6 Magnetic Fields Exert Forces on Currents
49 The Form of the Magnetic Force on a Current We learned that the magnetic field exerts no force on a charged particle moving parallel to a magnetic field. If a currentcarrying wire is parallel to a magnetic field, we also find that the force on it is zero. There is a force on a currentcarrying wire that is perpendicular to a magnetic field. Slide 2459
50 The right hand rule to determine magnetic force This right hand rule is a little different than what your book uses, but I think it s easier to remember. You must keep your hand in this configuration and turn your whole wrist!! F Point in the direction of the CURRENT (velocity of the charges). Turn your hand so that your middle finger (or three remaining fingers) point in the direction of the field. Your thumb gives you the direction of the force. v B Slide 2460
51 Calculating Magnetic Force on a Current Derive an equation that can be used to calculate magnetic force on a currentcarrying wire. Slide 2461
52 Review What is the equation for a magnetic force on a moving charge? F = qvbsinθ What if there are many moving charges, like a current in a wire? F F = = x q Bsinθ t q xbsinθ = t q t xbsinθ = x represents the length of the wire (the distance the charges move) I xbsinθ Slide 2462
53 Magnetic Force on Current Carrying Wire F B I: current in Amps l: length in meters B: magnetic field in Tesla θ: angle between current and field = IlB sinθ Slide 2463
54 Sample Problem What is the force on a 100 m long wire bearing a 30 A current flowing north if the wire is in a downwarddirected magnetic field of 400 mt? F F F B B B = IlB sinθ = ( )( )( m T) C s = 1200 N sin90 The force is west (use the right hand rule remember we assume positive charges are flowing in the wire). Slide 2465
55 Sample Problem A wire is in a magnetic field that is directed out of the page. What is the magnetic field strength if the current in the wire is 15 A and the force is downward and has a magnitude of 40 N/m? What is the direction of the current? ANS: 2.67 T, right Slide 2466
56 Which way will this loop of wire rotate a) if the current is clockwise? b) if the current is counterclockwise? B a) The right side of the loop will rotate out of the page. b) The right side of the loop will rotate into the page. Slide 2467
57 QuickCheck The horizontal wire can be levitated held up against the force of gravity if the current in the wire is A. Right to left. B. Left to right. C. It can t be done with this magnetic field. Slide 2470
58 QuickCheck The horizontal wire can be levitated held up against the force of gravity if the current in the wire is A. Right to left. B. Left to right. C. It can t be done with this magnetic field. Slide 2471
59 Example Magnetic force on a power line A DC power line near the equator runs eastwest. At this location, the earth s magnetic field is parallel to the ground, points north, and has magnitude 50 µt. A 400 m length of the heavy cable that spans the distance between two towers has a mass of 1000 kg. What direction and magnitude of current would be necessary to offset the force of gravity and levitate the wire? (The power line will actually carry a current that is much less than this; 850 A is a typical value.) Slide 2472
60 Example Magnetic force on a power line (cont.) PREPARE First, we sketch a top view of the situation, as in FIGURE The magnetic force on the wire must be opposite that of gravity. An application of the righthand rule for forces shows that a current to the east will result in an upward force out of the page. Slide 2473
61 Example Magnetic force on a power line (cont.) SOLVE The magnetic field is perpendicular to the current, so the magnitude of the magnetic force is given by Equation To levitate the wire, this force must be opposite to the weight force but equal in magnitude, so we can write mg = ILB where m and L are the mass and length of the wire and B is the magnitude of the earth s field. Solving for the current, we find directed to the east. Slide 2474
62 Example Magnetic force on a power line (cont.) ASSESS The current is much larger than a typical current, as we expected. Slide 2475
63 Forces Between Currents Because a current produces a magnetic field, and a magnetic field exerts a force on a current, it follows that two currentcarrying wires will exert forces on each other. A wire carrying a current I 1 will create a magnetic field 1. Slide 2476
64 Forces Between Currents A second wire with current I 2 will experience the magnetic force due to the wire with current I 1. Using the righthand rule for forces, we can see that when I 2 is in the same direction as I 1, the second wire is attracted to the first wire. If they were in opposite directions, the second wire would be repelled. Slide 2477
65 Forces Between Currents The magnetic field created by the wire with current I 2 will also exert an attractive force on the wire with current I 1. The forces on the two wires form a Newton s third law action/reaction pair. The forces due to the magnetic fields of the wires are directed in opposite directions and must have the same magnitude. Slide 2478
66 Forces Between Currents Slide 2479
67 Example Finding the force between wires in jumper cables You may have used a set of jumper cables connected to a running vehicle to start a car with a dead battery. Jumper cables are a matched pair of wires, red and black, joined together along their length. Suppose we have a set of jumper cables in which the two wires are separated by 1.2 cm along their 3.7 m (12 ft) length. While starting a car, the wires each carry a current of 150 A, in opposite directions. What is the force between the two wires? Slide 2480
68 Example Finding the force between wires in jumper cables (cont.) PREPARE Our first step is to sketch the situation, noting distances and currents, as shown in FIGURE Let s find the force on the red wire; from the discussion above, the force on the black wire has the same magnitude but is in the opposite direction. Slide 2481
69 Example Finding the force between wires in jumper cables (cont.) The force on the red wire is found using a twostep process. First, we find the magnetic field due to the current in the black wire at the position of the red wire. Then, we find the force on the current in the red wire due to this magnetic field. Slide 2482
70 Example Finding the force between wires in jumper cables (cont.) SOLVE The magnetic field at the position of the red wire, due to the current in the black wire, is According to the righthand rule for fields, this magnetic field is directed into the page. The magnitude of the force on the red wire is then Slide 2483
71 Example Finding the force between wires in jumper cables (cont.) The direction of the force can be found using the righthand rule for forces. The magnetic field at the position of the red wire is into the page, while the current is to the right. This means that the force on the red wire is in the plane of the page, directed away from the black wire. Thus the force between the two wires is repulsive, as we expect when their currents are directed oppositely. Slide 2484
72 Example Finding the force between wires in jumper cables (cont.) ASSESS These wires are long, close together, and carry very large currents. But the force between them is quite small much less than the weight of the wires. In practice, the forces between currents are not an important consideration unless there are many coils of wire, leading to a large total force. This is the case in an MRI solenoid. Slide 2485
73 Forces Between Current Loops Just as there is an attractive force between parallel wires that have currents in the same direction, there is an attractive force between parallel loops with currents in the same direction. There is a repulsive force between parallel loops with currents in opposite directions. Slide 2486
74 Forces Between Current Loops The field of a current loop is very similar to that of a bar magnet. A current loop, like a bar magnet, is a magnetic dipole with a north and a south pole. Slide 2487
75 Forces Between Current Loops Slide 2488
76 QuickCheck The diagram below shows slices through two adjacent current loops. Think about the force exerted on the loop on the right due to the loop on the left. The force on the right loop is directed A. To the left. B. Up. C. To the right. D. Down. Slide 2489
77 QuickCheck The diagram below shows slices through two adjacent current loops. Think about the force exerted on the loop on the right due to the loop on the left. The force on the right loop is directed A. To the left. B. Up. C. To the right. D. Down. Slide 2490
78 Example Problem A 10 cm length of wire carries a current of 3.0 A. The wire is in a uniform field with a strength of 5E3 Tesla as in the following diagram. What are the magnitude and direction of the force on this segment of wire? Slide 2491
79 Summary: General Principles Text: p. 794 Slide 2492
80 Summary: Important Concepts Text: p. 794 Slide 2493
81 Summary: Applications Text: p. 794 Slide 2494
Conceptual: 1, 3, 5, 6, 8, 16, 18, 19. Problems: 4, 6, 8, 11, 16, 20, 23, 27, 34, 41, 45, 56, 60, 65. Conceptual Questions
Conceptual: 1, 3, 5, 6, 8, 16, 18, 19 Problems: 4, 6, 8, 11, 16, 20, 23, 27, 34, 41, 45, 56, 60, 65 Conceptual Questions 1. The magnetic field cannot be described as the magnetic force per unit charge
More informationPhysics 112 Homework 5 (solutions) (2004 Fall) Solutions to Homework Questions 5
Solutions to Homework Questions 5 Chapt19, Problem2: (a) Find the direction of the force on a proton (a positively charged particle) moving through the magnetic fields in Figure P19.2, as shown. (b) Repeat
More informationMagnetism. d. gives the direction of the force on a charge moving in a magnetic field. b. results in negative charges moving. clockwise.
Magnetism 1. An electron which moves with a speed of 3.0 10 4 m/s parallel to a uniform magnetic field of 0.40 T experiences a force of what magnitude? (e = 1.6 10 19 C) a. 4.8 10 14 N c. 2.2 10 24 N b.
More informationChapter 22 Magnetism
22.6 Electric Current, Magnetic Fields, and Ampere s Law Chapter 22 Magnetism 22.1 The Magnetic Field 22.2 The Magnetic Force on Moving Charges 22.3 The Motion of Charged particles in a Magnetic Field
More information1. Units of a magnetic field might be: A. C m/s B. C s/m C. C/kg D. kg/c s E. N/C m ans: D
Chapter 28: MAGNETIC FIELDS 1 Units of a magnetic field might be: A C m/s B C s/m C C/kg D kg/c s E N/C m 2 In the formula F = q v B: A F must be perpendicular to v but not necessarily to B B F must be
More informationChapter 14 Magnets and
Chapter 14 Magnets and Electromagnetism How do magnets work? What is the Earth s magnetic field? Is the magnetic force similar to the electrostatic force? Magnets and the Magnetic Force! We are generally
More informationTIME OF COMPLETION DEPARTMENT OF NATURAL SCIENCES. PHYS 2212, Exam 2 Section 1 Version 1 April 16, 2014 Total Weight: 100 points
TIME OF COMPLETION NAME DEPARTMENT OF NATURAL SCIENCES PHYS 2212, Exam 2 Section 1 Version 1 April 16, 2014 Total Weight: 100 points 1. Check your examination for completeness prior to starting. There
More informationMagnetic Force. For centuries, humans observed strange force. Between iron and special stones called lodestones. Force couldn't be gravity or electric
MAGNETIC FIELD Magnetic Force For centuries, humans observed strange force Between iron and special stones called lodestones Force couldn't be gravity or electric Not enough mass or electric charge to
More informationPhysics 126 Practice Exam #3 Professor Siegel
Physics 126 Practice Exam #3 Professor Siegel Name: Lab Day: 1. Which one of the following statements concerning the magnetic force on a charged particle in a magnetic field is true? A) The magnetic force
More informationChapter 21. Magnetic Forces and Magnetic Fields
Chapter 21 Magnetic Forces and Magnetic Fields 21.1 Magnetic Fields The needle of a compass is permanent magnet that has a north magnetic pole (N) at one end and a south magnetic pole (S) at the other.
More informationChapter 19: Magnetic Forces and Fields
Chapter 19: Magnetic Forces and Fields Magnetic Fields Magnetic Force on a Point Charge Motion of a Charged Particle in a Magnetic Field Crossed E and B fields Magnetic Forces on Current Carrying Wires
More informationPhysics 30 Worksheet #10 : Magnetism From Electricity
Physics 30 Worksheet #10 : Magnetism From Electricity 1. Draw the magnetic field surrounding the wire showing electron current below. x 2. Draw the magnetic field surrounding the wire showing electron
More informationChapter 19 Magnetic Forces and Fields
Chapter 19 Magnetic Forces and Fields Student: 3. The magnetism of the Earth acts approximately as if it originates from a huge bar magnet within the Earth. Which of the following statements are true?
More informationPhysics 2B. Lecture 29B
Physics 2B Lecture 29B "There is a magnet in your heart that will attract true friends. That magnet is unselfishness, thinking of others first. When you learn to live for others, they will live for you."
More informationPhys222 Winter 2012 Quiz 4 Chapters 2931. Name
Name If you think that no correct answer is provided, give your answer, state your reasoning briefly; append additional sheet of paper if necessary. 1. A particle (q = 5.0 nc, m = 3.0 µg) moves in a region
More informationChapter 24 Practice Problems, Review, and Assessment
Section 1 Understanding Magnetism: Practice Problems 1. If you hold a bar magnet in each hand and bring your hands close together, will the force be attractive or repulsive if the magnets are held in the
More informationHomework #8 20311721 Physics 2 for Students of Mechanical Engineering. Part A
Homework #8 20311721 Physics 2 for Students of Mechanical Engineering Part A 1. Four particles follow the paths shown in Fig. 3233 below as they pass through the magnetic field there. What can one conclude
More informationMagnetic Field and Magnetic Forces
Chapter 27 Magnetic Field and Magnetic Forces PowerPoint Lectures for University Physics, Thirteenth Edition Hugh D. Young and Roger A. Freedman Lectures by Wayne Anderson Goals for Chapter 27 Magnets
More information1. The diagram below represents magnetic lines of force within a region of space.
1. The diagram below represents magnetic lines of force within a region of space. 4. In which diagram below is the magnetic flux density at point P greatest? (1) (3) (2) (4) The magnetic field is strongest
More informationCHARGE TO MASS RATIO OF THE ELECTRON
CHARGE TO MASS RATIO OF THE ELECTRON In solving many physics problems, it is necessary to use the value of one or more physical constants. Examples are the velocity of light, c, and mass of the electron,
More informationMagnets and the Magnetic Force
Magnets and the Magnetic Force We are generally more familiar with magnetic forces than with electrostatic forces. Like the gravitational force and the electrostatic force, this force acts even when the
More informationPhysics 1653 Exam 3  Review Questions
Physics 1653 Exam 3  Review Questions 3.0 Two uncharged conducting spheres, A and B, are suspended from insulating threads so that they touch each other. While a negatively charged rod is held near, but
More informationQuestion Details C14: Magnetic Field Direction Abbott [ ]
Phys 1114: Assignment 9 Abbott (5420633) Due: Mon Apr 7 2014 11:59 PM CDT Question 1 2 3 4 5 6 7 8 9 10 11 1. Question Details C14: Magnetic Field Direction Abbott [2861537] a) A wire is oriented horizontally
More informationCHARGED PARTICLES & MAGNETIC FIELDS  WebAssign
Name: Period: Due Date: Lab Partners: CHARGED PARTICLES & MAGNETIC FIELDS  WebAssign Purpose: Use the CP program from Vernier to simulate the motion of charged particles in Magnetic and Electric Fields
More informationPY106 Class13. Permanent Magnets. Magnetic Fields and Forces on Moving Charges. Interactions between magnetic north and south poles.
Permanent Magnets Magnetic ields and orces on Moing Charges 1 We encounter magnetic fields frequently in daily life from those due to a permanent magnet. Each permanent magnet has a north pole and a south
More informationExam 2 Solutions. PHY2054 Spring Prof. P. Kumar Prof. P. Avery March 5, 2008
Prof. P. Kumar Prof. P. Avery March 5, 008 Exam Solutions 1. Two cylindrical resistors are made of the same material and have the same resistance. The resistors, R 1 and R, have different radii, r 1 and
More informationAP2 Magnetism. (c) Explain why the magnetic field does no work on the particle as it moves in its circular path.
A charged particle is projected from point P with velocity v at a right angle to a uniform magnetic field directed out of the plane of the page as shown. The particle moves along a circle of radius R.
More informationMagnetic Fields and Forces. AP Physics B
Magnetic ields and orces AP Physics acts about Magnetism Magnets have 2 poles (north and south) Like poles repel Unlike poles attract Magnets create a MAGNETIC IELD around them Magnetic ield A bar magnet
More informationGeneral Physics (PHY 2140)
General Physics (PHY 2140) Lecture 12 Electricity and Magnetism Magnetism Magnetic fields and force Application of magnetic forces http://www.physics.wayne.edu/~apetrov/phy2140/ Chapter 19 1 Department
More informationMAGNETIC FORCE ON AN ELECTRIC CHARGE
DO PHYSICS ONLINE MOTORS AND GENERATORS MAGNETIC ORCE ON AN ELECTRIC CHARGE Experiments show that moing electric charges are deflected in magnetic fields. Hence, moing electric charges experience forces
More informationForce on Moving Charges in a Magnetic Field
[ Assignment View ] [ Eðlisfræði 2, vor 2007 27. Magnetic Field and Magnetic Forces Assignment is due at 2:00am on Wednesday, February 28, 2007 Credit for problems submitted late will decrease to 0% after
More informationChapter 27 Magnetic Field and Magnetic Forces
Chapter 27 Magnetic Field and Magnetic Forces  Magnetism  Magnetic Field  Magnetic Field Lines and Magnetic Flux  Motion of Charged Particles in a Magnetic Field  Applications of Motion of Charged
More informationPhysics 121 Sample Common Exam 3 NOTE: ANSWERS ARE ON PAGE 6. Instructions: 1. In the formula F = qvxb:
Physics 121 Sample Common Exam 3 NOTE: ANSWERS ARE ON PAGE 6 Signature Name (Print): 4 Digit ID: Section: Instructions: Answer all questions 24 multiple choice questions. You may need to do some calculation.
More informationName: Date: Regents Physics Mr. Morgante UNIT 4B Magnetism
Name: Regents Physics Date: Mr. Morgante UNIT 4B Magnetism Magnetism Magnetic Force exists b/w charges in motion. Similar to electric fields, an X stands for a magnetic field line going into the page,
More informationChapter 30  Magnetic Fields and Torque. A PowerPoint Presentation by Paul E. Tippens, Professor of Physics Southern Polytechnic State University
Chapter 30  Magnetic Fields and Torque A PowerPoint Presentation by Paul E. Tippens, Professor of Physics Southern Polytechnic State University 2007 Objectives: After completing this module, you should
More informationcircular motion & gravitation physics 111N
circular motion & gravitation physics 111N uniform circular motion an object moving around a circle at a constant rate must have an acceleration always perpendicular to the velocity (else the speed would
More informationSolution: (a) For a positively charged particle, the direction of the force is that predicted by the right hand rule. These are:
Problem 1. (a) Find the direction of the force on a proton (a positively charged particle) moving through the magnetic fields as shown in the figure. (b) Repeat part (a), assuming the moving particle is
More informationLab 4: Magnetic Force on Electrons
Lab 4: Magnetic Force on Electrons Introduction: Forces on particles are not limited to gravity and electricity. Magnetic forces also exist. This magnetic force is known as the Lorentz force and it is
More informationphysics 112N magnetic fields and forces
physics 112N magnetic fields and forces bar magnet & iron filings physics 112N 2 bar magnets physics 112N 3 the Earth s magnetic field physics 112N 4 electro magnetism! is there a connection between electricity
More informationMagnetism, a history. Existence of a Magnetic Field, B. Magnetic Force on a charged particle. The particle in the figure
Existence of a Magnetic Field, B Magnetic field, B, is a vector You may be familiar with bar magnets have a magnetic field similar to electric field of dipoles Amazing experimental finding: there is a
More information6/2016 E&M forces1/8 ELECTRIC AND MAGNETIC FORCES. PURPOSE: To study the deflection of a beam of electrons by electric and magnetic fields.
6/016 E&M forces1/8 ELECTRIC AND MAGNETIC FORCES PURPOSE: To study the deflection of a beam of electrons by electric and magnetic fields. APPARATUS: Electron beam tube, stand with coils, power supply,
More informationMagnetism: a new force!
1 Magnetism: a new force! So far, we'e learned about two forces: graity and the electric field force. =, = Definition of field kq fields are created by charges: = r field exerts a force on other charges:
More informationPhysics 2212 GH Quiz #4 Solutions Spring 2015
Physics 1 GH Quiz #4 Solutions Spring 15 Fundamental Charge e = 1.6 1 19 C Mass of an Electron m e = 9.19 1 31 kg Coulomb constant K = 8.988 1 9 N m /C Vacuum Permittivity ϵ = 8.854 1 1 C /N m Earth s
More informationReview Questions PHYS 2426 Exam 2
Review Questions PHYS 2426 Exam 2 1. If 4.7 x 10 16 electrons pass a particular point in a wire every second, what is the current in the wire? A) 4.7 ma B) 7.5 A C) 2.9 A D) 7.5 ma E) 0.29 A Ans: D 2.
More informationMy lecture slides are posted at Information for Physics 112 midterm, Wednesday, May 2
My lecture slides are posted at http://www.physics.ohiostate.edu/~humanic/ Information for Physics 112 midterm, Wednesday, May 2 1) Format: 10 multiple choice questions (each worth 5 points) and two showwork
More informationDate: Deflection of an Electron in a Magnetic Field
Name: Partners: Date: Deflection of an Electron in a Magnetic Field Purpose In this lab, we use a Cathode Ray Tube (CRT) to measure the effects of an electric and magnetic field on the motion of a charged
More informationThe Electric Force. From mechanics, the relationship for the gravitational force on an object is: m is the mass of the particle of interest,
. The Electric Force Concepts and Principles The Gravitational Analogy In introducing the concept of the electric field, I tried to illustrate it by drawing an analogy with the gravitational field, g.
More informationElectromagnetism Extra Study Questions Short Answer
Electromagnetism Extra Study Questions Short Answer 1. The electrostatic force between two small charged objects is 5.0 10 5 N. What effect would each of the following changes have on the magnitude of
More informationFall 12 PHY 122 Homework Solutions #8
Fall 12 PHY 122 Homework Solutions #8 Chapter 27 Problem 22 An electron moves with velocity v= (7.0i  6.0j)10 4 m/s in a magnetic field B= (0.80i + 0.60j)T. Determine the magnitude and direction of the
More informationCHAPTER 6 WORK AND ENERGY
CHAPTER 6 WORK AND ENERGY CONCEPTUAL QUESTIONS. REASONING AND SOLUTION The work done by F in moving the box through a displacement s is W = ( F cos 0 ) s= Fs. The work done by F is W = ( F cos θ). s From
More informationThe purposes of this experiment are to test Faraday's Law qualitatively and to test Lenz's Law.
260 171 I. THEORY EXPERIMENT 17 QUALITATIVE STUDY OF INDUCED EMF Along the extended central axis of a bar magnet, the magnetic field vector B r, on the side nearer the North pole, points away from this
More informationC B A T 3 T 2 T 1. 1. What is the magnitude of the force T 1? A) 37.5 N B) 75.0 N C) 113 N D) 157 N E) 192 N
Three boxes are connected by massless strings and are resting on a frictionless table. Each box has a mass of 15 kg, and the tension T 1 in the right string is accelerating the boxes to the right at a
More informationChapter 18 Electric Forces and Electric Fields. Key Concepts:
Chapter 18 Lectures Monday, January 25, 2010 7:33 AM Chapter 18 Electric Forces and Electric Fields Key Concepts: electric charge principle of conservation of charge charge polarization, both permanent
More informationModule 3 : Electromagnetism Lecture 13 : Magnetic Field
Module 3 : Electromagnetism Lecture 13 : Magnetic Field Objectives In this lecture you will learn the following Electric current is the source of magnetic field. When a charged particle is placed in an
More informationIMPORTANT NOTE ABOUT WEBASSIGN:
Week 8 homework IMPORTANT NOTE ABOUT WEBASSIGN: In the WebAssign versions of these problems, various details have been changed, so that the answers will come out differently. The method to find the solution
More informationNewton s Laws of Motion
Physics Newton s Laws of Motion Newton s Laws of Motion 4.1 Objectives Explain Newton s first law of motion. Explain Newton s second law of motion. Explain Newton s third law of motion. Solve problems
More informationQuiz: Work and Energy
Quiz: Work and Energy A charged particle enters a uniform magnetic field. What happens to the kinetic energy of the particle? (1) it increases (2) it decreases (3) it stays the same (4) it changes with
More informationA satellite of mass 5.00x10² kg is in a circular orbit of radius 2r around Earth. Then it is moved to a circular orbit radius of 3r.
Supplemental Questions A satellite of mass 5.00x10² kg is in a circular orbit of radius 2r around Earth. Then it is moved to a circular orbit radius of 3r. (a) Determine the satellite s GPE in orbit. (b)
More informationMFF 2a: Charged Particle and a Uniform Magnetic Field... 2
MFF 2a: Charged Particle and a Uniform Magnetic Field... 2 MFF2a RT1: Charged Particle and a Uniform Magnetic Field... 3 MFF2a RT2: Charged Particle and a Uniform Magnetic Field... 4 MFF2a RT3: Charged
More informationVIII. Magnetic Fields  Worked Examples
MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Physics 8.0 Spring 003 VIII. Magnetic Fields  Worked Examples Example : Rolling rod A rod with a mass m and a radius R is mounted on two parallel rails
More informationMultiple Choice Questions for Physics 1 BA113 Chapter 23 Electric Fields
Multiple Choice Questions for Physics 1 BA113 Chapter 23 Electric Fields 63 When a positive charge q is placed in the field created by two other charges Q 1 and Q 2, each a distance r away from q, the
More informationPHY231 Section 2, Form A March 22, 2012. 1. Which one of the following statements concerning kinetic energy is true?
1. Which one of the following statements concerning kinetic energy is true? A) Kinetic energy can be measured in watts. B) Kinetic energy is always equal to the potential energy. C) Kinetic energy is always
More informationHomework 4. problems: 5.61, 5.67, 6.63, 13.21
Homework 4 problems: 5.6, 5.67, 6.6,. Problem 5.6 An object of mass M is held in place by an applied force F. and a pulley system as shown in the figure. he pulleys are massless and frictionless. Find
More informationModern Physics Laboratory e/m with Teltron Deflection Tube
Modern Physics Laboratory e/m with Teltron Deflection Tube Josh Diamond & John Cummings Fall 2010 Abstract The deflection of an electron beam by electric and magnetic fields is observed, and the charge
More informationVELOCITY, ACCELERATION, FORCE
VELOCITY, ACCELERATION, FORCE velocity Velocity v is a vector, with units of meters per second ( m s ). Velocity indicates the rate of change of the object s position ( r ); i.e., velocity tells you how
More informationMagnetic Fields and Their Effects
Name Date Time to Complete h m Partner Course/ Section / Grade Magnetic Fields and Their Effects This experiment is intended to give you some handson experience with the effects of, and in some cases
More informationPhysics 9 Fall 2009 Homework 2  Solutions
Physics 9 Fall 009 Homework  s 1. Chapter 7  Exercise 5. An electric dipole is formed from ±1.0 nc charges spread.0 mm apart. The dipole is at the origin, oriented along the y axis. What is the electric
More informationUniversity Physics 226N/231N Old Dominion University. Newton s Laws and Forces Examples
University Physics 226N/231N Old Dominion University Newton s Laws and Forces Examples Dr. Todd Satogata (ODU/Jefferson Lab) satogata@jlab.org http://www.toddsatogata.net/2012odu Wednesday, September
More informationProfs. A. Petkova, A. Rinzler, S. Hershfield. Exam 2 Solution
PHY2049 Fall 2009 Profs. A. Petkova, A. Rinzler, S. Hershfield Exam 2 Solution 1. Three capacitor networks labeled A, B & C are shown in the figure with the individual capacitor values labeled (all units
More informationPHY121 #8 Midterm I 3.06.2013
PHY11 #8 Midterm I 3.06.013 AP Physics Newton s Laws AP Exam Multiple Choice Questions #1 #4 1. When the frictionless system shown above is accelerated by an applied force of magnitude F, the tension
More informationChapter 33. The Magnetic Field
Chapter 33. The Magnetic Field Digital information is stored on a hard disk as microscopic patches of magnetism. Just what is magnetism? How are magnetic fields created? What are their properties? These
More informationCET Moving Charges & Magnetism
CET 2014 Moving Charges & Magnetism 1. When a charged particle moves perpendicular to the direction of uniform magnetic field its a) energy changes. b) momentum changes. c) both energy and momentum
More informationMFF 3a: Charged Particle and a Straight CurrentCarrying Wire... 2
MFF 3a: Charged Particle and a Straight CurrentCarrying Wire... 2 MFF3a RT1: Charged Particle and a Straight CurrentCarrying Wire... 3 MFF3a RT2: Charged Particle and a Straight CurrentCarrying Wire...
More informationLab 9 Magnetic Interactions
Lab 9 Magnetic nteractions Physics 6 Lab What You Need To Know: The Physics Electricity and magnetism are intrinsically linked and not separate phenomena. Most of the electrical devices you will encounter
More informationPrelab Quiz/PHYS 224 Magnetic Force and Current Balance. Your name Lab section
Prelab Quiz/PHYS 224 Magnetic Force and Current Balance Your name Lab section 1. What do you investigate in this lab? 2. Two straight wires are in parallel and carry electric currents in opposite directions
More informationElectrostaticsE Field
1. Which diagram represents the electric field lines between two small electrically charged spheres? 2. Which graph best represents the relationship between the magnitude of the electric field strength,
More informationExam 2 Practice Problems Part 2 Solutions
Problem 1: Short Questions MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Physics 8. Exam Practice Problems Part Solutions (a) Can a constant magnetic field set into motion an electron, which is initially
More informationPHY231 Section 1, Form B March 22, 2012
1. A car enters a horizontal, curved roadbed of radius 50 m. The coefficient of static friction between the tires and the roadbed is 0.20. What is the maximum speed with which the car can safely negotiate
More information2.1 Force and Motion Kinematics looks at velocity and acceleration without reference to the cause of the acceleration.
2.1 Force and Motion Kinematics looks at velocity and acceleration without reference to the cause of the acceleration. Dynamics looks at the cause of acceleration: an unbalanced force. Isaac Newton was
More information356 CHAPTER 12 Bob Daemmrich
Standard 7.3.17: Investigate that an unbalanced force, acting on an object, changes its speed or path of motion or both, and know that if the force always acts toward the same center as the object moves,
More informationChapter 3.8 & 6 Solutions
Chapter 3.8 & 6 Solutions P3.37. Prepare: We are asked to find period, speed and acceleration. Period and frequency are inverses according to Equation 3.26. To find speed we need to know the distance traveled
More informationEðlisfræði 2, vor 2007
[ Assignment View ] [ Pri Eðlisfræði 2, vor 2007 28. Sources of Magnetic Field Assignment is due at 2:00am on Wednesday, March 7, 2007 Credit for problems submitted late will decrease to 0% after the deadline
More informationNewton s Third Law. object 1 on object 2 is equal in magnitude and opposite in direction to the force exerted by object 2 on object 1
Newton s Third Law! If two objects interact, the force exerted by object 1 on object 2 is equal in magnitude and opposite in direction to the force exerted by object 2 on object 1!! Note on notation: is
More informationCharged Particle in a Magnetic Field
Charged Particle in a Magnetic Field Consider a particle moving in an external magnetic field with its velocity perpendicular to the field The force is always directed toward the center of the circular
More informationCandidate Number. General Certificate of Education Advanced Level Examination June 2010
entre Number andidate Number Surname Other Names andidate Signature General ertificate of Education dvanced Level Examination June 1 Physics PHY4/1 Unit 4 Fields and Further Mechanics Section Friday 18
More information104 Practice Exam 23/21/02
104 Practice Exam 23/21/02 1. Two electrons are located in a region of space where the magnetic field is zero. Electron A is at rest; and electron B is moving westward with a constant velocity. A nonzero
More informationPHYS 222 Spring 2012 Final Exam. Closed books, notes, etc. No electronic device except a calculator.
PHYS 222 Spring 2012 Final Exam Closed books, notes, etc. No electronic device except a calculator. NAME: (all questions with equal weight) 1. If the distance between two point charges is tripled, the
More informationB) 40.8 m C) 19.6 m D) None of the other choices is correct. Answer: B
Practice Test 1 1) Abby throws a ball straight up and times it. She sees that the ball goes by the top of a flagpole after 0.60 s and reaches the level of the top of the pole after a total elapsed time
More informationElectrostatics Problems
Name AP Physics B Electrostatics Problems Date Mrs. Kelly 1. How many excess electrons are contained in a charge of 30 C? 2. Calculate and compare the gravitational and electrostatic force between an electron
More informationCh 6 Forces. Question: 9 Problems: 3, 5, 13, 23, 29, 31, 37, 41, 45, 47, 55, 79
Ch 6 Forces Question: 9 Problems: 3, 5, 13, 23, 29, 31, 37, 41, 45, 47, 55, 79 Friction When is friction present in ordinary life?  car brakes  driving around a turn  walking  rubbing your hands together
More information= Ps cos 0 = (150 N)(7.0 m) = J F N. s cos 180 = µ k
Week 5 homework IMPORTANT NOTE ABOUT WEBASSIGN: In the WebAssign versions o these problems, various details have been changed, so that the answers will come out dierently. The method to ind the solution
More informationProgetto Orientamento in rete
Progetto Orientamento in rete Unità 1: Newton s law of gravitation and Gravitational field Unità 2: Gravitational potential energy Unità 3: Coulomb s law and Electric field Unità 4: Magnetic field Prof.ssa
More informationChapter 29: Magnetic Fields
Chapter 29: Magnetic Fields Magnetism has been known as early as 800C when people realized that certain stones could be used to attract bits of iron. Experiments using magnets hae shown the following:
More informationE/M Experiment: Electrons in a Magnetic Field.
E/M Experiment: Electrons in a Magnetic Field. PRELAB You will be doing this experiment before we cover the relevant material in class. But there are only two fundamental concepts that you need to understand.
More informationChapter 6. Work and Energy
Chapter 6 Work and Energy The concept of forces acting on a mass (one object) is intimately related to the concept of ENERGY production or storage. A mass accelerated to a nonzero speed carries energy
More informationPhysics 2A, Sec B00: Mechanics  Winter 2011 Instructor: B. Grinstein Final Exam
Physics 2A, Sec B00: Mechanics  Winter 2011 Instructor: B. Grinstein Final Exam INSTRUCTIONS: Use a pencil #2 to fill your scantron. Write your code number and bubble it in under "EXAM NUMBER;" an entry
More information) 0.7 =1.58 10 2 N m.
Exam 2 Solutions Prof. Paul Avery Prof. Andrey Korytov Oct. 29, 2014 1. A loop of wire carrying a current of 2.0 A is in the shape of a right triangle with two equal sides, each with length L = 15 cm as
More informationChapter 5 Using Newton s Laws: Friction, Circular Motion, Drag Forces. Copyright 2009 Pearson Education, Inc.
Chapter 5 Using Newton s Laws: Friction, Circular Motion, Drag Forces Units of Chapter 5 Applications of Newton s Laws Involving Friction Uniform Circular Motion Kinematics Dynamics of Uniform Circular
More informationFORCE ON A CURRENT IN A MAGNETIC FIELD
7/16 Force current 1/8 FORCE ON A CURRENT IN A MAGNETIC FIELD PURPOSE: To study the force exerted on an electric current by a magnetic field. BACKGROUND: When an electric charge moves with a velocity v
More informationv v ax v a x a v a v = = = Since F = ma, it follows that a = F/m. The mass of the arrow is unchanged, and ( )
Week 3 homework IMPORTANT NOTE ABOUT WEBASSIGN: In the WebAssign versions of these problems, various details have been changed, so that the answers will come out differently. The method to find the solution
More information