2015 Pearson Education, Inc. Section 24.5 Magnetic Fields Exert Forces on Moving Charges
|
|
|
- Albert Weaver
- 7 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 24-3
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 24-4
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 24-5
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 right-hand rule for forces. Slide 24-7
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 24-8
9 Magnetic Fields Exert Forces on Moving Charges Slide 24-9
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 24-10
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 24-11
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 24-12
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 24-13
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 24-14
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 24-15
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 24-16
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 24-17
18 QuickCheck Which magnetic field causes the observed force? Slide 24-18
19 QuickCheck Which magnetic field causes the observed force? C. Slide 24-19
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 24-20
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 24-23
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 24-24
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 24-25
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 24-26
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 24-27
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 24-28
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 24-29
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 24-30
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 24-32
33 Paths of Charged Particles in Magnetic Fields Slide 24-33
34 Paths of Charged Particles in Magnetic Fields Slide 24-34
35 Paths of Charged Particles in Magnetic Fields High-energy 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 24-35
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 24-36
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 24-37
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 24-40
39 QuickCheck Which magnetic field (if it s the correct strength) allows the electron to pass through the charged electrodes without being deflected? Slide 24-41
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 24-42
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 24-43
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 24-44
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 24-45
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 24-46
45 Electromagnetic Flowmeters Slide 24-47
46 Electromagnetic Flowmeters Slide 24-48
47 Don t Try It Yourself: Magnets and Television Screens The image on a cathode-ray 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 24-57
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 current-carrying 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 24-59
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 24-60
51 Calculating Magnetic Force on a Current Derive an equation that can be used to calculate magnetic force on a current-carrying wire. Slide 24-61
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 24-62
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 24-63
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 24-65
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 24-66
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 24-67
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 24-70
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 24-71
59 Example Magnetic force on a power line A DC power line near the equator runs east-west. 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 24-72
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 right-hand rule for forces shows that a current to the east will result in an upward force out of the page. Slide 24-73
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 24-74
62 Example Magnetic force on a power line (cont.) ASSESS The current is much larger than a typical current, as we expected. Slide 24-75
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 24-76
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 right-hand 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 24-77
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 24-78
66 Forces Between Currents Slide 24-79
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 24-80
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 24-81
69 Example Finding the force between wires in jumper cables (cont.) The force on the red wire is found using a two-step 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 24-82
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 right-hand rule for fields, this magnetic field is directed into the page. The magnitude of the force on the red wire is then Slide 24-83
71 Example Finding the force between wires in jumper cables (cont.) The direction of the force can be found using the right-hand 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 24-84
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 24-85
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 24-86
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 24-87
75 Forces Between Current Loops Slide 24-88
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 24-89
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 24-90
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 5E-3 Tesla as in the following diagram. What are the magnitude and direction of the force on this segment of wire? Slide 24-91
79 Summary: General Principles Text: p. 794 Slide 24-92
80 Summary: Important Concepts Text: p. 794 Slide 24-93
81 Summary: Applications Text: p. 794 Slide 24-94
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
Physics 112 Homework 5 (solutions) (2004 Fall) Solutions to Homework Questions 5
Solutions to Homework Questions 5 Chapt19, Problem-2: (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
Magnetism. 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.
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 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
Chapter 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
Chapter 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.
Physics 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
Chapter 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
Physics 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."
Chapter 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?
Magnetic 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
Phys222 Winter 2012 Quiz 4 Chapters 29-31. 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
1. 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
PY106 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
CHARGED 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
Magnetic 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
AP2 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.
Force 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
General 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
Chapter 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
Physics 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.
Lab 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
circular 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
Chapter 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
physics 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
6/2016 E&M forces-1/8 ELECTRIC AND MAGNETIC FORCES. PURPOSE: To study the deflection of a beam of electrons by electric and magnetic fields.
6/016 E&M forces-1/8 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,
Electromagnetism 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
Review 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.
The purposes of this experiment are to test Faraday's Law qualitatively and to test Lenz's Law.
260 17-1 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
CHAPTER 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
C 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
Quiz: 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
VELOCITY, 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
Magnetic 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 hands-on experience with the effects of, and in some cases
MFF 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
How To Understand The Physics Of A Charge Charge
MFF 3a: Charged Particle and a Straight Current-Carrying Wire... 2 MFF3a RT1: Charged Particle and a Straight Current-Carrying Wire... 3 MFF3a RT2: Charged Particle and a Straight Current-Carrying Wire...
PHY231 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
Modern 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
PHY121 #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
Exam 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
Chapter 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
Chapter 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
Pre-lab Quiz/PHYS 224 Magnetic Force and Current Balance. Your name Lab section
Pre-lab 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
PHY231 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
Eðlisfræði 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
104 Practice Exam 2-3/21/02
104 Practice Exam 2-3/21/02 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 non-zero
Charged 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
Candidate 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
Chapter 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 non-zero speed carries energy
Chapter 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:
PHYS 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
E/M Experiment: Electrons in a Magnetic Field.
E/M Experiment: Electrons in a Magnetic Field. PRE-LAB 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.
Chapter 22: Electric motors and electromagnetic induction
Chapter 22: Electric motors and electromagnetic induction The motor effect movement from electricity When a current is passed through a wire placed in a magnetic field a force is produced which acts on
Chapter 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
v 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
Physics 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
Magnetism Basics. Magnetic Domains: atomic regions of aligned magnetic poles Random Alignment Ferromagnetic Alignment. Net Effect = Zero!
Magnetism Basics Source: electric currents Magnetic Domains: atomic regions of aligned magnetic poles Random Alignment Ferromagnetic Alignment Net Effect = Zero! Net Effect = Additive! Bipolar: all magnets
FORCE 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
ElectroMagnetic Induction. AP Physics B
ElectroMagnetic Induction AP Physics B What is E/M Induction? Electromagnetic Induction is the process of using magnetic fields to produce voltage, and in a complete circuit, a current. Michael Faraday
F N A) 330 N 0.31 B) 310 N 0.33 C) 250 N 0.27 D) 290 N 0.30 E) 370 N 0.26
Physics 23 Exam 2 Spring 2010 Dr. Alward Page 1 1. A 250-N force is directed horizontally as shown to push a 29-kg box up an inclined plane at a constant speed. Determine the magnitude of the normal force,
Candidate Number. General Certificate of Education Advanced Level Examination June 2012
entre Number andidate Number Surname Other Names andidate Signature General ertificate of Education dvanced Level Examination June 212 Physics PHY4/1 Unit 4 Fields and Further Mechanics Section Monday
Physics 111: Lecture 4: Chapter 4 - Forces and Newton s Laws of Motion. Physics is about forces and how the world around us reacts to these forces.
Physics 111: Lecture 4: Chapter 4 - Forces and Newton s Laws of Motion Physics is about forces and how the world around us reacts to these forces. Whats a force? Contact and non-contact forces. Whats a
TEACHER ANSWER KEY November 12, 2003. Phys - Vectors 11-13-2003
Phys - Vectors 11-13-2003 TEACHER ANSWER KEY November 12, 2003 5 1. A 1.5-kilogram lab cart is accelerated uniformly from rest to a speed of 2.0 meters per second in 0.50 second. What is the magnitude
Halliday, Resnick & Walker Chapter 13. Gravitation. Physics 1A PHYS1121 Professor Michael Burton
Halliday, Resnick & Walker Chapter 13 Gravitation Physics 1A PHYS1121 Professor Michael Burton II_A2: Planetary Orbits in the Solar System + Galaxy Interactions (You Tube) 21 seconds 13-1 Newton's Law
Magnetic Fields. I. Magnetic Field and Magnetic Field Lines
Magnetic Fields I. Magnetic Field and Magnetic Field Lines A. The concept of the magnetic field can be developed in a manner similar to the way we developed the electric field. The magnitude of the magnetic
Physics Midterm Review Packet January 2010
Physics Midterm Review Packet January 2010 This Packet is a Study Guide, not a replacement for studying from your notes, tests, quizzes, and textbook. Midterm Date: Thursday, January 28 th 8:15-10:15 Room:
Motion of Charges in Combined Electric and Magnetic Fields; Measurement of the Ratio of the Electron Charge to the Electron Mass
Motion of Charges in Combined Electric and Magnetic Fields; Measurement of the Ratio of the Electron Charge to the Electron Mass Object: Understand the laws of force from electric and magnetic fields.
Q27.1 When a charged particle moves near a bar magnet, the magnetic force on the particle at a certain point depends
Q27.1 When a charged particle moves near a bar magnet, the magnetic force on the particle at a certain point depends A. on the direction of the magnetic field at that point only. B. on the magnetic field
Physics: Principles and Applications, 6e Giancoli Chapter 4 Dynamics: Newton's Laws of Motion
Physics: Principles and Applications, 6e Giancoli Chapter 4 Dynamics: Newton's Laws of Motion Conceptual Questions 1) Which of Newton's laws best explains why motorists should buckle-up? A) the first law
Linear DC Motors. 15.1 Magnetic Flux. 15.1.1 Permanent Bar Magnets
Linear DC Motors The purpose of this supplement is to present the basic material needed to understand the operation of simple DC motors. This is intended to be used as the reference material for the linear
Unit 4 Practice Test: Rotational Motion
Unit 4 Practice Test: Rotational Motion Multiple Guess Identify the letter of the choice that best completes the statement or answers the question. 1. How would an angle in radians be converted to an angle
III. Applications of Force and Motion Concepts. Concept Review. Conflicting Contentions. 1. Airplane Drop 2. Moving Ball Toss 3. Galileo s Argument
III. Applications of Force and Motion Concepts Concept Review Conflicting Contentions 1. Airplane Drop 2. Moving Ball Toss 3. Galileo s Argument Qualitative Reasoning 1. Dropping Balls 2. Spinning Bug
PHYS 211 FINAL FALL 2004 Form A
1. Two boys with masses of 40 kg and 60 kg are holding onto either end of a 10 m long massless pole which is initially at rest and floating in still water. They pull themselves along the pole toward each
Introduction to Magnetic Fields
Chapter 8 Introduction to Magnetic Fields 8.1 Introduction...8-2 8.2 The Definition of a Magnetic Field...8-3 8.3 Magnetic Force on a Current-Carrying Wire...8-4 Example 8.1: Magnetic Force on a Semi-Circular
Measurement of Charge-to-Mass (e/m) Ratio for the Electron
Measurement of Charge-to-Mass (e/m) Ratio for the Electron Experiment objectives: measure the ratio of the electron charge-to-mass ratio e/m by studying the electron trajectories in a uniform magnetic
PS-6.2 Explain the factors that determine potential and kinetic energy and the transformation of one to the other.
PS-6.1 Explain how the law of conservation of energy applies to the transformation of various forms of energy (including mechanical energy, electrical energy, chemical energy, light energy, sound energy,
F B = ilbsin(f), L x B because we take current i to be a positive quantity. The force FB. L and. B as shown in the Figure below.
PHYSICS 176 UNIVERSITY PHYSICS LAB II Experiment 9 Magnetic Force on a Current Carrying Wire Equipment: Supplies: Unit. Electronic balance, Power supply, Ammeter, Lab stand Current Loop PC Boards, Magnet
Induced voltages and Inductance Faraday s Law
Induced voltages and Inductance Faraday s Law concept #1, 4, 5, 8, 13 Problem # 1, 3, 4, 5, 6, 9, 10, 13, 15, 24, 23, 25, 31, 32a, 34, 37, 41, 43, 51, 61 Last chapter we saw that a current produces a magnetic
Faraday s Law of Induction
Chapter 10 Faraday s Law of Induction 10.1 Faraday s Law of Induction...10-10.1.1 Magnetic Flux...10-3 10.1. Lenz s Law...10-5 10. Motional EMF...10-7 10.3 Induced Electric Field...10-10 10.4 Generators...10-1
Newton s Law of Universal Gravitation
Newton s Law of Universal Gravitation The greatest moments in science are when two phenomena that were considered completely separate suddenly are seen as just two different versions of the same thing.
www.mathsbox.org.uk Displacement (x) Velocity (v) Acceleration (a) x = f(t) differentiate v = dx Acceleration Velocity (v) Displacement x
Mechanics 2 : Revision Notes 1. Kinematics and variable acceleration Displacement (x) Velocity (v) Acceleration (a) x = f(t) differentiate v = dx differentiate a = dv = d2 x dt dt dt 2 Acceleration Velocity
45. The peak value of an alternating current in a 1500-W device is 5.4 A. What is the rms voltage across?
PHYS Practice Problems hapters 8- hapter 8. 45. The peak value of an alternating current in a 5-W device is 5.4 A. What is the rms voltage across? The power and current can be used to find the peak voltage,
LAB 6: GRAVITATIONAL AND PASSIVE FORCES
55 Name Date Partners LAB 6: GRAVITATIONAL AND PASSIVE FORCES And thus Nature will be very conformable to herself and very simple, performing all the great Motions of the heavenly Bodies by the attraction
4 Gravity: A Force of Attraction
CHAPTER 1 SECTION Matter in Motion 4 Gravity: A Force of Attraction BEFORE YOU READ After you read this section, you should be able to answer these questions: What is gravity? How are weight and mass different?
Physics 11 Assignment KEY Dynamics Chapters 4 & 5
Physics Assignment KEY Dynamics Chapters 4 & 5 ote: for all dynamics problem-solving questions, draw appropriate free body diagrams and use the aforementioned problem-solving method.. Define the following
At the skate park on the ramp
At the skate park on the ramp 1 On the ramp When a cart rolls down a ramp, it begins at rest, but starts moving downward upon release covers more distance each second When a cart rolls up a ramp, it rises
Physics 221 Experiment 5: Magnetic Fields
Physics 221 Experiment 5: Magnetic Fields August 25, 2007 ntroduction This experiment will examine the properties of magnetic fields. Magnetic fields can be created in a variety of ways, and are also found
Name Class Period. F = G m 1 m 2 d 2. G =6.67 x 10-11 Nm 2 /kg 2
Gravitational Forces 13.1 Newton s Law of Universal Gravity Newton discovered that gravity is universal. Everything pulls on everything else in the universe in a way that involves only mass and distance.
Sample Questions for the AP Physics 1 Exam
Sample Questions for the AP Physics 1 Exam Sample Questions for the AP Physics 1 Exam Multiple-choice Questions Note: To simplify calculations, you may use g 5 10 m/s 2 in all problems. Directions: Each
Physics 41, Winter 1998 Lab 1 - The Current Balance. Theory
Physics 41, Winter 1998 Lab 1 - The Current Balance Theory Consider a point at a perpendicular distance d from a long straight wire carrying a current I as shown in figure 1. If the wire is very long compared
Worksheet #1 Free Body or Force diagrams
Worksheet #1 Free Body or Force diagrams Drawing Free-Body Diagrams Free-body diagrams are diagrams used to show the relative magnitude and direction of all forces acting upon an object in a given situation.
Chapter 3 Falling Objects and Projectile Motion
Chapter 3 Falling Objects and Projectile Motion Gravity influences motion in a particular way. How does a dropped object behave?!does the object accelerate, or is the speed constant?!do two objects behave
Candidate Number. General Certificate of Education Advanced Level Examination June 2014
entre Number andidate Number Surname Other Names andidate Signature General ertificate of Education dvanced Level Examination June 214 Physics PHY4/1 Unit 4 Fields and Further Mechanics Section Wednesday
Exam 1 Review Questions PHY 2425 - Exam 1
Exam 1 Review Questions PHY 2425 - Exam 1 Exam 1H Rev Ques.doc - 1 - Section: 1 7 Topic: General Properties of Vectors Type: Conceptual 1 Given vector A, the vector 3 A A) has a magnitude 3 times that
5. Forces and Motion-I. Force is an interaction that causes the acceleration of a body. A vector quantity.
5. Forces and Motion-I 1 Force is an interaction that causes the acceleration of a body. A vector quantity. Newton's First Law: Consider a body on which no net force acts. If the body is at rest, it will
CHAPTER 16 -- MAGNETIC FIELDS QUESTION & PROBLEM SOLUTIONS
Solutions--Ch. 16 (Magnetic Fields) CHAPTER 16 -- MAGNETIC FIELDS QUESTION & PROBLEM SOLUTIONS 16.1) What is the symbol for a magnetic field? What are its units? Also, what are magnetic fields, really?
LAB 6 - GRAVITATIONAL AND PASSIVE FORCES
L06-1 Name Date Partners LAB 6 - GRAVITATIONAL AND PASSIVE FORCES OBJECTIVES And thus Nature will be very conformable to herself and very simple, performing all the great Motions of the heavenly Bodies
Practice final for Basic Physics spring 2005 answers on the last page Name: Date:
Practice final for Basic Physics spring 2005 answers on the last page Name: Date: 1. A 12 ohm resistor and a 24 ohm resistor are connected in series in a circuit with a 6.0 volt battery. Assuming negligible
Curso2012-2013 Física Básica Experimental I Cuestiones Tema IV. Trabajo y energía.
1. A body of mass m slides a distance d along a horizontal surface. How much work is done by gravity? A) mgd B) zero C) mgd D) One cannot tell from the given information. E) None of these is correct. 2.