# Chapter 29. Magnetic Fields

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 Chapter 29 Magnetic Fields

2 A Partial History of Magnetism 13 th century BC Chinese used a compass 800 BC Uses a magnetic needle Probably an invention of Arabic or Indian origin Greeks Discovered magnetite (Fe 3 O 4 ) attracts iron

3 A Partial History of Magnetism Hans Christian Oersted Danish Physicist Discovered the relationship between electricity and magnetism in 1819 during a lecture demonstration! An electric current in a wire deflected a nearby compass needle

4 Demo Ec4: Oersted s Experiment When a current flows through the conductor the compass needle deflects due to the magnetic field set up by the current. Reversing the direction of the current reverses the direction of the magnetic field. Oersted in 1819 revolutionised the study of electricity & magnetism, sparking scientists to investigate the subject. He himself couldn t set up experiments and had to rely on assistants. He got left behind!

5 Demo Ec1: Lines of force in a magnetic field Iron filings sprinkled onto perspex sheet on top of bar magnet

6 Magnetic Poles Every magnet, regardless of its shape, has two poles Called north and south poles Poles exert forces on one another Similar to the way electric charges exert forces on each other Like poles repel N-N or S-S Unlike poles attract N-S

7 Magnetic Poles, cont. The poles received their names due to the way a magnet behaves in the Earth s magnetic field If a bar magnet is suspended so that it can move freely, it will rotate Magnetic north pole points toward the Earth s north geographic pole i.e. Earth s north geographic pole is a magnetic south pole Similarly, the Earth s south geographic pole is a magnetic north pole

8 Magnetic Poles, final The force between two poles varies as the inverse square of the distance between them A single magnetic pole has never been isolated i.e. magnetic poles always found in pairs There is some theoretical basis for the existence of monopoles single poles

9 Magnetic Fields (magnetic induction) A vector quantity Symbol B Direction given by that which the north pole of a compass needle points Magnetic field lines trace this direction in space

10 MFA02VD1: Compass needle shows direction of magnetic field around a bar magnet

11 Magnetic Field Lines for a Bar Magnet Compass can be used to trace the field lines The lines outside the magnet point from the North pole to the South pole

12 MFM02VD1: Magnetic Field lines around bar magnets

13 Magnetic Field Lines, Bar Magnet Iron filings are used to show the pattern of the magnetic field lines The direction of the field is the direction a north pole would point

14 Magnetic Field Lines, Unlike Poles Iron filings are used to show the pattern of the electric field lines The direction of the field is the direction a north pole would point c.f. electric field produced by an electric dipole

15 Magnetic Field Lines, Like Poles Iron filings are used to show the pattern of the electric field lines The direction of the field is the direction a north pole would point c.f. electric field produced by like charges

16 Magnetic Fields and Forces The magnetic field, B, at some point in space can be defined in terms of the magnetic force, F B Note: B is sometimes known as the Magnetic Induction A magnetic force will be exerted on a charged particle moving in a magnetic field

17 F B on a Charge Moving in a Magnetic Field Magnitude proportional to charge and speed of the particle Direction depends on the velocity of the particle and the direction of the magnetic field It is perpendicular to both F B = q v x B F B is the magnetic force q is the charge v is the velocity of the moving charge B is the magnetic field

18 Direction F B perpendicular to plane formed by v & B Oppositely directed forces are exerted on charges of different signs cause the particles to move in opposite directions

19 Direction given by Right-Hand Rule Fingers point in the direction of v (for positive charge; opposite direction if negative) Curl fingers in the direction of B Then thumb points in the direction of v x B; i.e. the direction of F B

20 The Magnitude of F The magnitude of the magnetic force on a charged particle is F B = q vb sin is the angle between v and B F B is zero when v and B are parallel or antiparallel = 0 or 180 F B is a maximum when v and B are perpendicular = 90

21 Example Proton moves at v = 8x10 6 m/s in x-direction. Enters region where B = 2.5 T directed at 60 to x-axis in xy-plane. What is the initial force on the proton? Right Hand rule puts F in the z-direction. F qvb sin( ) ( C)( m/s)(2.5 T)sin(60 ) N. Tiny!

22 Differences Between Electric and Magnetic Fields Direction of force Electric force acts along direction of electric field Magnetic force acts perpendicular to magnetic field Motion Electric force acts on a charged particle regardless of whether the particle is moving Magnetic force acts on a charged particle only when the particle is in motion

23 Differences Between Electric and Magnetic Fields Work Electric force does work in displacing a charged particle Magnetic force associated with a steady magnetic field does no work when a particle is displaced Force is perpendicular to the displacement, so F.ds=0

24 Work in Magnetic Fields The kinetic energy of a charged particle moving through a magnetic field cannot be altered by the magnetic field alone The field can only alter the direction of the particle, not its speed

25 Units of Magnetic Field The SI unit of magnetic field is the tesla (T) Since F B = q vb sin 1 T 1 The cgs unit is a gauss (G) 1 T = 10 4 G N C m/s 1 N A m

26 Typical Magnetic Field Values

27 Quick Quiz 29.1 The north-pole end of a bar magnet is held near a positively charged piece of plastic. The plastic is (a) attracted (b) repelled (c) unaffected by the magnet

28 Quick Quiz 29.1 Answer: (c). The magnetic force exerted by a magnetic field on a charge is proportional to the charge s velocity relative to the field. If the charge is stationary, as in this situation, there is no magnetic force.

29 Quick Quiz 29.2 A charged particle moves with velocity v in a magnetic field B. The magnetic force on the particle is a maximum when v is: (a) parallel to B (b) perpendicular to B (c) zero

30 Quick Quiz 29.2 Answer: (b). The maximum value of sin θ occurs for θ = 90.

31 Quick Quiz 29.3 An electron moves in the plane of this paper toward the top of the page. A magnetic field is also in the plane of the page and directed toward the right. The direction of the magnetic force on the electron is (a) toward the top of the page (b) toward the bottom of the page (c) toward the left edge of the page (d) toward the right edge of the page (e) out of the page (f) into the page

32 Quick Quiz 29.3 Answer: (e). Out of the page. The right-hand rule gives the direction. Be sure to account for the negative charge on the electron.

33 Magnetic Force on a Current Carrying Conductor A force is exerted on a current-carrying wire placed in a magnetic field The current is a collection of many charged particles in motion The direction of the force is given by the right-hand rule

34 Ec9: Magnetic force on current carrying conductor Flexible wire placed between poles of a strong magnet. When current is passed through it, the wire dramatically jumps out. Can demonstrate F is perpendicular to L and B by suspending wire in different orientations. See also corridor display.

35 Note on Notation The dots indicate the direction is out of the page The dots represent the tips of the arrows coming toward you The crosses indicate the direction is into the page The crosses represent the feathered tails of the arrows

36 MFA03AN2: Force on a current-carrying conductor

37 Force on a Wire When no current flows there is no force Therefore, the wire remains vertical

38 Force on a Wire (2) With B into the page, and Current up the page, then Force is to the left Apply the right hand rule

39 Force on a Wire, equation Magnetic force is exerted on each moving charge in the wire F = q v d x B Total force is the product of force on one charge times the number of charges F = (q v d x B)nAL n is the number of charges per unit volume

40 Force on a Wire, (4) In terms of the current, this becomes F = I L x B L is a vector that points in the direction of the current (i.e. of v D ) Magnitude is the length L of the segment I is the current = nqav D (think about the units to see this) B is the magnetic field

41 Force on a Wire of Arbitrary Shape Consider a small segment of the wire, ds The force exerted on this segment is F = I ds x B The total force is a b F I d s B

42 Force on a Wire, Case 1 Suppose that B is uniform. b Then a F I d s B becomes F=I L xb L is the vector sum of all the length elements from a to b Thus, the magnetic force on a curved currentcarrying wire in a uniform field is equal to that on a straight wire connecting the end points and carrying the same current

43 Force on a Wire, Case 2 An arbitrary shaped closed loop carrying current I in a uniform magnetic field F B I d s B 0 since d s 0 The length elements form a closed loop, so the vector sum is zero Thus, the net magnetic force acting on any closed current loop in a uniform magnetic field is zero

44 Quick Quiz 29.4 The four wires shown below all carry the same current from point A to point B through the same magnetic field. In all four parts of the figure, the points A and B are 10 cm apart. Which of the following choices ranks the wires according to the magnitude of the magnetic force exerted on them, from greatest to least? (a) a, b, c (b) a, c, b (c) a, c, d (d) a, d, c (d) b, c, d (e) c, b, d

45 Quick Quiz 29.4 Answer: (c). The order is (a), (b) = (c), (d). The magnitude of the force depends on the value of sin θ. The maximum force occurs when the wire is perpendicular to the field (a), and there is zero force when the wire is parallel (d). Choices (b) and (c) represent the same force because a straight wire between A and B will have the same force on it as the curved wire for a uniform magnetic field.

46 Quick Quiz 29.5 A wire carries current in the plane of this paper towards the top of the page. The wire experiences a magnetic force toward the right edge of the page. The direction of the magnetic field causing this force is (a) in the plane of the page and toward the left edge (b) in the plane of the page and toward the bottom edge (c) out of the page (d) into the page

47 Quick Quiz 29.5 Answer: (c). Use the right-hand rule to determine the direction of the magnetic field.

48 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 centre of the circular path The magnetic force causes a centripetal acceleration, changing the direction of the velocity of the particle

49 Force on a Charged Particle Equating the magnetic and centripetal forces: Solving gives r = mv/qb F qvb mv 2 r r is proportional to the momentum of the particle and inversely proportional to the charge and to the magnetic field

50 More About Motion of Charged Particle The angular speed of the particle is v r qb m The angular speed, is also referred to as the cyclotron frequency The period of the motion is T 2 r v 2 2 m qb

51 Van Allen Radiation Belts The Van Allen radiation belts consist of charged particles surrounding the Earth in doughnut-shaped regions Cosmic ray particles from the Sun are trapped by the Earth s magnetic field The particles spiral from pole to pole Can result in Auroras

52 The Earth s Magnetosphere Charged particles trapped in the Van Allen belts and create aurorae

53 Aurorae: MFM11VD1 Typically km above the Earth

54 Ec5: Deflection of electron beam by magnetic & electric fields Use either a cathode ray tube or electron beam deflection tube. Possible to determine e/m by size of the deflection. Mark North pole of magnet to show that F = q v x B.

55 MFM03AN1: Lorentz force in electric & magnetic fields

56 Charged Particles Moving in Electric and Magnetic Fields In many applications, charged particles will move in the presence of both magnetic and electric fields In that case, the total force is the sum of the forces due to the individual fields In general: F = qe + qv x B

57 Hall Effect (not examinable) When a current carrying conductor is placed in a magnetic field, a potential difference is generated in a direction perpendicular to both the current and the magnetic field This phenomena is known as the Hall effect It arises from the deflection of charge carriers to one side of the conductor as a result of the magnetic forces they experience

58 Hall Voltage Observing the Hall effect The Hall voltage is measured between points a and c

59 Hall Effect When the charge carriers are negative, the upper edge of the conductor becomes negatively charged When the charge carriers are positive, the upper edge becomes positively charged Sign of Hall voltage, V H, gives the sign of the charges

60 Hall Voltage In equilibrium qe H = qv d B V H = E H d = v d B d d is the width of the conductor v d is the drift velocity So can be found if B and d are known and V H measured Since v d I nqa, then V H IBd nqa Where R H = 1 / nq is called the Hall coefficient and y is the thickness of the conductor, with area A = yd A properly calibrated conductor can be used to measure the magnitude of an unknown magnetic field IB nqy R H IB y

61 Quick Quiz 29.8 A charged particle is moving perpendicular to a magnetic field in a circle with a radius r. An identical particle enters the field, with v perpendicular to B, but with a higher speed v than the first particle. Compared to the radius of the circle for the first particle, the radius of the circle for the second particle is (a) smaller (b) larger (c) equal in size

62 Quick Quiz 29.8 Answer: (b). The magnetic force on the particle increases in proportion to v, but the centripetal acceleration increases according to the square of v. The result is a larger radius, as we can see from r = mv/qb.

63 Quick Quiz 29.9 A charged particle is moving perpendicular to a magnetic field in a circle with a radius r. The magnitude of the magnetic field is increased. Compared to the initial radius of the circular path, the radius of the new path is (a) smaller (b) larger (c) equal in size

64 Quick Quiz 29.9 Answer: (a). The magnetic force on the particle increases in proportion to B. The result is a smaller radius, as we also see from r = mv/qb.

65 End of Chapter

66 Quick Quiz 29.6 Rank the magnitudes of the torques acting on the rectangular loops shown in the figure below, from highest to lowest. (All the loops are identical and carry the same current.) (a) a, b, c (b) b, c, a (c) c, b, a (d) a, c, b. (e) All loops experience zero torque.

67 Quick Quiz 29.6 Answer: (c). Because all loops enclose the same area and carry the same current, the magnitude of μ is the same for all. For part (c) in the image, μ points upward and is perpendicular to the magnetic field and τ = μb, the maximum torque possible. For the loop in (a), μ points along the direction of B and the torque is zero. For (b), the torque is intermediate between zero and the maximum value.

68 Quick Quiz 29.7 Rank the magnitudes of the net forces acting on the rectangular loops shown in this figure, from highest to lowest. (All the loops are identical and carry the same current.) (a) a, b, c (b) b, c, a (c) c, b, a (d) b, a, c (e) All loops experience zero net force.

69 Quick Quiz 29.7 Answer: (e). Because the magnetic field is uniform, there is zero net force on all three loops.

70 Quick Quiz 29.10a Three types of particles enter a mass spectrometer like the one shown in your book as Figure The figure below shows where the particles strike the detector array. Rank the particles that arrive at a, b, and c by speed. (a) a, b, c (c) c, b, a (b) b, c, a (d) All their speeds are equal.

71 Quick Quiz 29.10a Answer: (d). The velocity selector ensures that all three types of particles have the same speed.

72 Quick Quiz 29.10b Rank the particles that arrive at a, b, and c by m/q ratio. (a) a, b, c (c) c, b, a (b) b, c, a (d) All their m/q ratios are equal.

73 Quick Quiz 29.10b Answer: (c). We cannot determine individual masses or charges, but we can rank the particles by m/q ratio. Equation indicates that those particles traveling through the circle of greatest radius have the greatest m/q ratio.

### 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 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

### 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

### 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

### 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

### 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 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

### 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.

### Module 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

### TIME 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

### 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

### 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.

### CHARGE 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,

### Fall 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

### 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

### Lecture 14. Magnetic Forces on Currents.

Lecture 14. Magnetic Forces on Currents. Outline: Hall Effect. Magnetic Force on a Wire Segment. Torque on a Current-Carrying Loop. Lecture 13: Magnetic Forces on Moving Charges - we considered individual

### 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

### MAGNETIC 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

### 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

### Magnetic 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

### 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 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:

### Solution: (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

### 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

### 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.

### 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

### 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

### Homework #8 203-1-1721 Physics 2 for Students of Mechanical Engineering. Part A

Homework #8 203-1-1721 Physics 2 for Students of Mechanical Engineering Part A 1. Four particles follow the paths shown in Fig. 32-33 below as they pass through the magnetic field there. What can one conclude

### Magnetism, 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

### 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."

### Magnets 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

### 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

### 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

### 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

### Name: 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,

### 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

### 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

### Physics 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

### * Biot Savart s Law- Statement, Proof Applications of Biot Savart s Law * Magnetic Field Intensity H * Divergence of B * Curl of B. PPT No.

* Biot Savart s Law- Statement, Proof Applications of Biot Savart s Law * Magnetic Field Intensity H * Divergence of B * Curl of B PPT No. 17 Biot Savart s Law A straight infinitely long wire is carrying

### CET 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

### Section V.4: Cross Product

Section V.4: Cross Product Definition The cross product of vectors A and B is written as A B. The result of the cross product A B is a third vector which is perpendicular to both A and B. (Because the

### 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?

### My lecture slides are posted at Information for Physics 112 midterm, Wednesday, May 2

My lecture slides are posted at http://www.physics.ohio-state.edu/~humanic/ Information for Physics 112 midterm, Wednesday, May 2 1) Format: 10 multiple choice questions (each worth 5 points) and two show-work

### VIII. 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

### 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

### 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

### 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

### 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.

### Date: 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

### Question 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

### 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

### 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

### Lab 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

### 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

### Ampere's Law. Introduction. times the current enclosed in that loop: Ampere's Law states that the line integral of B and dl over a closed path is 0

1 Ampere's Law Purpose: To investigate Ampere's Law by measuring how magnetic field varies over a closed path; to examine how magnetic field depends upon current. Apparatus: Solenoid and path integral

### MFF 3a: Charged Particle and a Straight Current-Carrying Wire... 2

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...

### Chapter 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

### Magnetism: 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:

### Physics 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

### 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

### Magnetic Dipoles. Recall that an electric dipole consists of two equal but opposite charges separated by some distance, such as in

MAGNETISM History of Magnetism Bar Magnets Magnetic Dipoles Magnetic Fields Magnetic Forces on Moving Charges and Wires Electric Motors Current Loops and Electromagnets Solenoids Sources of Magnetism Spin

### Profs. 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

### 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

### ELECTRICITYt. Electromagnetism

ELECTRICITYt Electromagnetism Subject area : Physics Topic focus : magnetic properties, magnetic field, the Earth s magnetic field, magnetic field of an electric wire. Learning Aims : Polarity of bar magnets

### 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

### 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

### Chapter 8: Magnetism

8.1 The Force on a Charge in a Magnetic Field - The Definition of the Magnetic Field esides the existence of electric fields in nature, there are also magnetic fields. Most students have seen and played

### 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

### 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

### MAGNETIC EFFECTS OF ELECTRIC CURRENT

CHAPTER 13 MAGNETIC EFFECT OF ELECTRIC CURRENT In this chapter, we will study the effects of electric current : 1. Hans Christian Oersted (1777-1851) Oersted showed that electricity and magnetism are related

### The DC Motor. Physics 1051 Laboratory #5 The DC Motor

The DC Motor Physics 1051 Laboratory #5 The DC Motor Contents Part I: Objective Part II: Introduction Magnetic Force Right Hand Rule Force on a Loop Magnetic Dipole Moment Torque Part II: Predictions Force

### Solving Simultaneous Equations and Matrices

Solving Simultaneous Equations and Matrices The following represents a systematic investigation for the steps used to solve two simultaneous linear equations in two unknowns. The motivation for considering

### Exam 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

### Magnetism. Magnetism. Magnetic Fields and Magnetic Domains. Magnetic Fields and Magnetic Domains. Creating and Destroying a Magnet

Magnetism Magnetism Opposite poles attract and likes repel Opposite poles attract and likes repel Like electric force, but magnetic poles always come in pairs (North, South) Like electric force, but magnetic

### LAB 8: Electron Charge-to-Mass Ratio

Name Date Partner(s) OBJECTIVES LAB 8: Electron Charge-to-Mass Ratio To understand how electric and magnetic fields impact an electron beam To experimentally determine the electron charge-to-mass ratio.

### 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.

### Q28.1 A positive point charge is moving to the right. The magnetic field that the point charge produces at point P (see diagram below) P

Q28.1 A positive point charge is moving to the right. The magnetic field that the point charge produces at point P (see diagram below) P r + v r A. points in the same direction as v. B. points from point

### Physics Spring Experiment #8 1 Experiment #8, Magnetic Forces Using the Current Balance

Physics 182 - Spring 2012 - Experiment #8 1 Experiment #8, Magnetic Forces Using the Current Balance 1 Purpose 1. To demonstrate and measure the magnetic forces between current carrying wires. 2. To verify

### Experiment 7: Forces and Torques on Magnetic Dipoles

MASSACHUSETTS INSTITUTE OF TECHNOLOY Department of Physics 8. Spring 5 OBJECTIVES Experiment 7: Forces and Torques on Magnetic Dipoles 1. To measure the magnetic fields due to a pair of current-carrying

### Physics, Chapter 30: Magnetic Fields of Currents

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Robert Katz Publications Research Papers in Physics and Astronomy 1-1-1958 Physics, Chapter 30: Magnetic Fields of Currents

### PHYS-2020: General Physics II Course Lecture Notes Section V

PHYS-2020: General Physics II Course Lecture Notes Section V Dr. Donald G. Luttermoser East Tennessee State University Edition 4.0 Abstract These class notes are designed for use of the instructor and

### Lecture 13. Magnetic Field, Magnetic Forces on Moving Charges. Outline:

Lecture 13. Magnetic Field, Magnetic Forces on Moving Charges. Outline: Intro to Magnetostatics. Magnetic Field Flux, Absence of Magnetic Monopoles. Force on charges moving in magnetic field. 1 Intro to

### Figure 1.1 Vector A and Vector F

CHAPTER I VECTOR QUANTITIES Quantities are anything which can be measured, and stated with number. Quantities in physics are divided into two types; scalar and vector quantities. Scalar quantities have

### 6/06 Ampere's Law. Ampere's Law. Andre-Marie Ampere in France felt that if a current in a wire exerted a magnetic

About this lab: Ampere's Law Andre-Marie Ampere in France felt that if a current in a wire exerted a magnetic force on a compass needle, two such wires also should interact magnetically. Beginning within

### Magnetic Force on a Current-Carrying Wire

Title: Original Version: Revision: Authors: Appropriate Level: Abstract: Time Required: NY Standards Met: AP Physics Learning Objective: Magnetic Force on a Current-Carrying Wire 11 November 2006 24 June

### 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.

### Magnetic fields of charged particles in motion

C H A P T E R 8 Magnetic fields of charged particles in motion CONCEPTS 8.1 Source of the magnetic field 8. Current loops and spin magnetism 8.3 Magnetic moment and torque 8.4 Ampèrian paths QUANTTATVE

### 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

### Magnetism. ***WARNING: Keep magnets away from computers and any computer disks!***

Magnetism This lab is a series of experiments investigating the properties of the magnetic field. First we will investigate the polarity of magnets and the shape of their field. Then we will explore the

### MAGNETISM MAGNETISM. Principles of Imaging Science II (120)

Principles of Imaging Science II (120) Magnetism & Electromagnetism MAGNETISM Magnetism is a property in nature that is present when charged particles are in motion. Any charged particle in motion creates

### 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

Last Name: First Name: Physics 102 Spring 2006: Exam #2 Multiple-Choice Questions 1. A charged particle, q, is moving with speed v perpendicular to a uniform magnetic field. A second identical charged

### Physics 9 Fall 2009 Homework 7 - Solutions

Physics 9 Fall 009 Homework 7 - s 1. Chapter 33 - Exercise 10. At what distance on the axis of a current loop is the magnetic field half the strength of the field at the center of the loop? Give your answer

### 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

### 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

### Magnetic Field & Right Hand Rule. Academic Resource Center

Magnetic Field & Right Hand Rule Academic Resource Center Magnetic Fields And Right Hand Rules By: Anthony Ruth Magnetic Fields vs Electric Fields Magnetic fields are similar to electric fields, but they

### Mapping the Magnetic Field

I Mapping the Magnetic Field Mapping the Magnetic Field Vector Fields The electric field, E, and the magnetic field, B, are two examples of what are termed vector fields, quantities which have both magnitude

### Force on a square loop of current in a uniform B-field.

Force on a square loop of current in a uniform B-field. F top = 0 θ = 0; sinθ = 0; so F B = 0 F bottom = 0 F left = I a B (out of page) F right = I a B (into page) Assume loop is on a frictionless axis