LAB 8: Electron ChargetoMass Ratio


 Harvey Golden
 11 months ago
 Views:
Transcription
1 Name Date Partner(s) OBJECTIVES LAB 8: Electron ChargetoMass Ratio To understand how electric and magnetic fields impact an electron beam To experimentally determine the electron chargetomass ratio. OVERVIEW In this experiment, you will measure e/m, the ratio of the electron s charge e to its mass m. Given that it is also possible to perform a measurement of e alone (the Millikan Oil Drop Experiment), it is possible to obtain the value of the mass of the electron, a very small quantity. If a particle carrying an electric charge q moves with a velocity v in a magnetic field B that is at a right angle to the direction of motion, it will experience the Lorentz force: F = q v x B, (1) which, because of the vector product, is always perpendicular to both the magnetic field and the direction of motion. A constant force that is always perpendicular to the direction of motion will cause a particle to move in a circle. We will use this fact to determine e/m of the electron by measuring the radius of that circle. To this end we must: produce a narrow beam of electrons of known energy, produce a uniform magnetic field, find a way to measure the radius r of the circular orbit of the electrons in that magnetic field find the relation between that radius and the ratio e/m. We discuss these problems in order. The Electron Beam When one heats a piece of metal, say a wire, to 1000 K or beyond, electrons will "boil off" from its surface. If one surrounds the wire with a positively charged electrode, an anode, the electrons will be attracted to it and move radially outward as indicated in Fig. 1. On their way to the anode they will acquire a kinetic energy Fig. 1: Electron gun. Electrons are produced by the hot cathode at the center. A voltage V between the cathode and anode accelerates the electron through a hole in the anode, so the electrons have kinetic energy ev.
2 Here, V is the potential difference, or voltage, between the heated filament, called the cathode, and the anode. Most of the electrons will strike the anode. However, if one cuts a narrow slit into the anode, those electrons that started out toward the slit will exit through it as a narrow beam with a kinetic energy Ek. The Magnetic Field According to Ampere's law a wire carrying a current I is surrounded by a magnetic field B, as shown in Fig. 2. If the wire is bent into a circle the field lines from all sides reinforce each other at the center, creating an axial field (see Fig. 3). Usually one will not use a single loop of wire to create a field but a coil with many turns. Fig. 2. Magnetic field of a straight wire. Fig. 3. Magnetic field of a wire loop. If one uses two coaxial coils of radius R that are a distance d apart, as shown in Fig. 4, the field at the center point between the coils will be nearly homogeneous. H. von Helmholtz ( ) realized that when d = R, the result is a particularly homogeneous field in the central region between the coils. In fact, both db/dx and d 2 B/dx 2 vanish at the center, where x is the distance along the axis from the middle point. Since that time Helmholtz coils have been used when there is a need for homogeneous magnetic fields.
3 Fig. 4. Magnetic field B of a pair of Helmholtz coils. R is the radius of the coils and d is the spacing between them. One can show that the field in the center of a Helmholtz coil is given by where I is the current flowing through both coils, R is their mean radius, N is the number of turns of wire in each coil, and µ0 = 4!x107 Tm/A is the permeability constant.
4 The Electron Orbit Experiments like the one that you will perform have been used to measure the mass of charged particles with great precision. In these experiments the particles move in a circular arc whose beginning and end are measured very accurately in a near perfect vacuum. For our simple experiment we cannot go to such lengths and a simple expedient has been used to make the electron orbit visible. The bulb surrounding the electron source is filled with an inert gas. When the electrons collide with the gas atoms, the atoms emit light so that one can follow the path of the electron beam. These collisions will diminish the accuracy of the experiment but it remains adequate for our purposes. A particle moving in a circle of radius r must be held there by a centripetal force: In our case, that centripetal force is the Lorentz force, equation (1), so we can write: This equation contains the velocity v, which we can eliminate by using the relationship between the electron kinetic energy and the accelerating voltage from equation (2): Therefore: In this equation, V is the voltage between cathode and anode and r is the mean radius of the circular electron orbit, both of which can be measured, and B is the magnetic field through which the electrons pass. We know the magnetic field at the center of the Helmholtz coil, which can be obtained from a measurement of the current through the coils, the dimension of the coils and the number of turns. The magnetic field does not change very much away from the center of the coils. Equipment: Voltmeter Ammeter Electron beam tube and Helmholtz coils 6.3V A.C. filament power supply to heat beam tube filament and produce free electrons Adjustable 0300V D.C. power supply for electron beam acceleration in beam tube Adjustable 02A D.C. power supply for current to Helmholtz coils to produce magnetic field Computer running Graphical Analysis or some other graphical software
5 Activity 11: Field Produced by the Helmholz Coils 1. First, record the number of turns and the radius of the Helmholtz coils you are using: Number of Turns (N) = Radius of Coil (R) = 2. Now, using the formula given in the Overview, calculate the value of the magnetic field at the center of the coils. Enter the value below. Bcenter = 3. The Earth s magnetic field is approximately 104 T. Discuss how much difficulty the Earth s magnetic field will cause in your experiment. Question 11: In what direction should the apparatus be aligned to minimize the effects of the Earth's magnetic field? Explain. (We can t really realign the apparatus this way, but you should think about it ) Is there a way to do the experiment so that you can completely cancel the effects of the earth s field? 4. Turn on the power supplies. Allow the filament of the electron tube to warm up for a minute or so. Set the current I in the Helmholtz coils to some value around 1.0A. When the filament is hot, slowly turn up the accelerating voltage Va and observe the path of the electrons. (DO NOT EXCEED 300V.) If the path of the beam is not perpendicular to the magnetic field, grasp the lowest part of the base of the tube and rotate it, being VERY CAREFUL not to pull or break any wires. 5. Vary the accelerating voltage while keeping the coil current constant. Again, DO NOT EXCEED 300V. Question 12: Now that you have observed the beam, and given that you know the sign of the electron s charge, what is the direction of the magnetic field produced by the coils? How do you know? For fun, you can change the polarity by switching the leads, just to see what happens. Question 13: What do you observe as the anode voltage is changed while keeping the coil current is constant? Explain why this occurs.
6 6. Vary the current in the coils (not to exceed 2.0A) and observe the bending of the beam. Reverse the current to the coils and observe the effect. (Then go back to the original polarity.) Observe the path of the electrons when the tube is rotated slightly away from the perpendicular position and record your observations. Question 14: What happens to the beam of electrons as the coil current is increased? Question 15: What causes the phenomena that you just described in Question 14? 7. Set the coil current and the anode voltage so that the electron beam has a radius of approximately half of the tube radius. Use the bar magnet to see how it affects the electron beam. We prefer that you not place the bar magnet above the glass tube, but you may move it around the bottom and the sides. Question 16: Describe what you observe as you move the bar magnet around. Can you produce a helical path for the electron? Can you see why you want to keep spurious magnetic fields away from the electron beam? 8. Make sure you place the bar magnet at the other end of the table from your apparatus to minimize any possible effects. Activity 12: Measurement of the Electron ChargetoMass Ratio This part of the experiment is broken up into two sections: measuring the radii of electron trajectories with fixed anode voltage by varying the magnetic field, or with fixed magnetic field and varying anode voltage. You should refer to the figures on the next page for further explanation. Part 1: Orbit Radius vs. B, Fixed Anode Voltage 9 Position the electron beam perpendicular to the magnetic field. 10 Now set Va at a value of!175v (or greater, if you are unable to see an entire circle of electron beam) and record Va. Keep Va at this same value for all of this section. The magnetic field B is varied by changing the current I. 11 The mean radius r of the electron beam's circular path is determined by measuring the positions of the inner and outer edges of the beam, x 1, x 2, x 3, x 4. (See figure on next page.) When you measure these values, try to line up the image of the beam in the mirror with the actual beam, so as to be sure you are viewing the scale perpendicularly to avoid reading errors due to parallax. The inner radius r 1 and outer radius r 2 of the beam are then given by:
7 12 The current should be set at! 1A (or the lowest value to give a full circular beam). Measure the values Va, I, x 1, x 2, x 3, x 4 and tabulate them using Graphical Analysis or DataStudio. 13 Change I and repeat part 4. for two additional I values (not to exceed 2.0A). (Each student in the group should take readings at least once.) When this is complete, each group should have a table of the measured radius for each of 3 different values of I, all for the same value of Va.
8 Definition of Measurement Variables:
9 Part 2: Orbit Radius vs. Anode Voltage, Fixed B 1 Set I back to one of the values used in Part 1. Keep I at this same value for all of Part 2. 2 Make and record sets of independent measurements of Va, I, and x 1, x 2, x 3, x 4 as in Part 1. for a total of three Va values different from the value used in part B. (Do not exceed Va = 300V.) 3 When this is complete, each group should have measurements for each of 4 different values of Va (including the value from Part 1) in a data table, all for the same value of I. We recommend you use Graphical Analysis or DataStudio for tabulation; this will make later analysis much easier. Activity 13: Analysis For the two different sets of measurements, we can manipulate the formulae given above to generate straight lines, which definitely makes the fitting easier. For the case with constant anode voltage and varying B, we can rewrite equation (3) to look like so a fit of 1/r vs B should give you something proportional to e/m. Likewise, rearranging equation (3) in a different way gives and you can do a similar fit. 1 Plot your data for both Part 1 and Part 2 in something like the manner suggested above. 2 For each plot, perform a linear fit, and include the parameters on the plot. 3 Print the plots out to turn in with your lab report. 4 Extract e/m from each of the plots. The accepted value is 1.7 x C/kg. How does yours compare? Questions: 1 There were many assumptions that were made in obtaining equation (3) which are not exactly true. List as many of these assumptions as you can (within reason) and estimate which of them would cause the greatest systematic error in your measurement. 2 Many students will answer that equation (3) does not account for special relativity. Calculate the speed of electrons for a typical accelerating voltage in this experiment. Relativistic effects are only important if the electron is moving at a significant fraction of the speed of light. Are they important here? 3 What effect could the presence of the earth s magnetic field have had on your results? End of Lab Checklist: Please turn off all power supplies and multimeters when you are finished.
Lab 5  Electron ChargetoMass Ratio
Lab 5 Electron ChargetoMass Ratio L51 Name Date Partners Lab 5  Electron ChargetoMass Ratio OBJECTIVES To understand how electric and magnetic fields impact an electron beam To experimentally determine
More informationMeasurement of ChargetoMass (e/m) Ratio for the Electron
Measurement of ChargetoMass (e/m) Ratio for the Electron Experiment objectives: measure the ratio of the electron chargetomass ratio e/m by studying the electron trajectories in a uniform magnetic
More informationStudy the effects of electric and magnetic fields on a charged particle and measure the chargetomass ratio (e/m) of the electron.
Experiment 2 The Ratio e/m for Electrons 2.1 Objective Study the effects of electric and magnetic fields on a charged particle and measure the chargetomass ratio (e/m) of the electron. 2.2 Theory In
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 informationCharge to mass ratio of the electron
1. Introduction Charge to mass ratio of the electron Julia Velkovska September 2006 In this lab you will repeat a classic experiment which was first performed by J.J. Thomson at the end of the 19 th century.
More informationPhysics 19. Charge to Mass Ratio of the Electron
Physics 19 Charge to Mass Ratio of the Electron Revised 9/2012, ABG Theory Elementary particle physics has as its goal to know the properties of the many atomic and subatomic particles (mesons, quarks,
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 informationqv x B FORCE: ELECTRONS IN A MAGNETIC FIELD
qv x B Force 91 qv x B FORCE: ELECTRONS IN A MAGNETIC FIELD Objectives: To see the effect of a magnetic field on a moving charge directly. To also measure the specific charge of electrons i.e. the ratio
More informationMAGNETISM LAB: The ChargetoMass Ratio of the Electron
Physics 9 Chargetomass: e/m p. 1 NAME: SECTION NUMBER: TA: LAB PARTNERS: MAGNETISM LAB: The ChargetoMass Ratio of the Electron Introduction In this lab you will explore the motion of a charged particle
More informationThe Charge to Mass Ratio (e/m) Ratio of the Electron. NOTE: You will make several sketches of magnetic fields during the lab.
The Charge to Mass Ratio (e/m) Ratio of the Electron NOTE: You will make several sketches of magnetic fields during the lab. Remember to include these sketches in your lab notebook as they will be part
More informationElectron Charge to Mass Ratio e/m
Electron Charge to Mass Ratio e/m J. Lukens, B. Reid, A. Tuggle PH 35001, Group 4 18 January 010 Abstract We have repeated with some modifications an 1897 experiment by J. J. Thompson investigating the
More informationEXPERIMENT IV. FORCE ON A MOVING CHARGE IN A MAGNETIC FIELD (e/m OF ELECTRON ) AND. FORCE ON A CURRENT CARRYING CONDUCTOR IN A MAGNETIC FIELD (µ o )
1 PRINCETON UNIVERSITY PHYSICS 104 LAB Physics Department Week #4 EXPERIMENT IV FORCE ON A MOVING CHARGE IN A MAGNETIC FIELD (e/m OF ELECTRON ) AND FORCE ON A CURRENT CARRYING CONDUCTOR IN A MAGNETIC FIELD
More informationMotion 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.
More informationElectron Charge to Mass Ratio Matthew Norton, Chris Bush, Brian Atinaja, Becker Steven. Norton 0
Electron Charge to Mass Ratio Matthew Norton, Chris Bush, Brian Atinaja, Becker Steven Norton 0 Norton 1 Abstract The electron charge to mass ratio was an experiment that was used to calculate the ratio
More informationJ. J. Thomson's Measurement of e/m for the electron
Physics 165 Laboratory J. J. Thomson's Measurement of e/m for the electron In 1897, the cathode ray tube or CRT, which is now a part of most TV sets, was the last word in advanced laboratory instrumentation
More informationCharged Particles Moving in an Magnetic Field
rev 12/2016 Charged Particles Moving in an Magnetic Field Equipment for Part 1 Qty Item Parts Number 1 Magnetic Field Sensor CI6520A 1 Zero Gauss Chamber EM8652 1 Dip Needle SF8619 1 Angle Indicator
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 informationPHY222 Lab 7  Magnetic Fields and Right Hand Rules Magnetic forces on wires, electron beams, coils; direction of magnetic field in a coil
PHY222 Lab 7  Magnetic Fields and Right Hand Rules Magnetic forces on wires, electron beams, coils; direction of magnetic field in a coil Print Your Name Print Your Partners' Names You will return this
More informationPHYS 345 Laboratory: Charge to Mass Ratio of the Electron
PHYS 345 Laboratory: Charge to Mass Ratio of the Electron Purpose: Apparatus: To determine the charge to mass ratio of the electron and compare it with the accepted value. CENCO e/m apparatus (electron
More informationCharge and Mass of the Electron
PHY 19 Charge and Mass of the Electron 1 Charge and Mass of the Electron Motivation for the Experiment The aim of this experiment is to measure the charge and mass of the electron. The charge will be measured
More informationEXPERIMENT #4 Charge to Mass ratio of the Electron
EXPERIMENT #4 Charge to Mass ratio of the Electron GOALS Physics Measure the chargetomass ratio e/m for electrons of a given kinetic energy moving in a magnetic field. Technique A low pressure Hg gas
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 informationCharge to Mass Ratio of the Electron
Charge to Mass Ratio of the Electron Purpose: Students will observe the interaction between a magnetic field and an electron beam, and measure the charge to mass ratio of the electron. Historical Introduction:
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 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 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 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 information4.1.Motion Of Charged Particles In Electric And Magnetic Field Motion Of Charged Particles In An Electric Field
4.1.Motion Of Charged Particles In Electric And Magnetic Field 4.1.1. Motion Of Charged Particles In An Electric Field A charged particle in an electric field will experience an electric force due to 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 informationPearson Physics Level 30 Unit VI Forces and Fields: Chapter 12 Solutions
Concept Check (top) Pearson Physics Level 30 Unit VI Forces and Fields: Chapter 1 Solutions Student Book page 583 Concept Check (bottom) The northseeking needle of a compass is attracted to what is called
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 informationPhysics 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
More informationChapter 5. Magnetic Fields and Forces. 5.1 Introduction
Chapter 5 Magnetic Fields and Forces Helmholtz coils and a gaussmeter, two of the pieces of equipment that you will use in this experiment. 5.1 Introduction Just as stationary electric charges produce
More informationHandout 7: Magnetic force. Magnetic force on moving charge
1 Handout 7: Magnetic force Magnetic force on moving charge A particle of charge q moving at velocity v in magnetic field B experiences a magnetic force F = qv B. The direction of the magnetic force is
More informationElectron Diffraction
Electron Diffraction Do moving electrons display wave nature? To answer this question you will direct a beam of electrons through a thin layer of carbon and analyze the resulting pattern. Theory Louis
More informationElectron Diffraction
1. Introduction Electron Diffraction Julia Velkovska, Oct 2006 In this experiment you will explore the waveparticle duality. You will do so by observing electron diffraction. The goal will be to test
More informationChapter 19 Magnetism Magnets Poles of a magnet are the ends where objects are most strongly attracted Two poles, called north and south Like poles
Chapter 19 Magnetism Magnets Poles of a magnet are the ends where objects are most strongly attracted Two poles, called north and south Like poles repel each other and unlike poles attract each other Similar
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 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 informationMagnets. We have all seen the demonstration where you put a magnet under a piece of glass, put some iron filings on top and see the effect.
Magnets We have all seen the demonstration where you put a magnet under a piece of glass, put some iron filings on top and see the effect. What you are seeing is another invisible force field known as
More informationTHE MAGNETIC FIELD. 9. Magnetism 1
THE MAGNETIC FIELD Magnets always have two poles: north and south Opposite poles attract, like poles repel If a bar magnet is suspended from a string so that it is free to rotate in the horizontal plane,
More informationHSC Physics SAMPLE LECTURE SLIDES
HSC SAMPLE LECTURE SLIDES HSC Exam Preparation Programs 4October2015 c 2015 Sci School TM.Allrightsreserved. Overview By the 1850 s vacuum pumps had become efficient enough to reduce the pressure inside
More informationHome Work 9. i 2 a 2. a 2 4 a 2 2
Home Work 9 91 A square loop of wire of edge length a carries current i. Show that, at the center of the loop, the of the magnetic field produced by the current is 0i B a The center of a square is a distance
More information1 of 7 4/13/2010 8:05 PM
Chapter 33 Homework Due: 8:00am on Wednesday, April 7, 2010 Note: To understand how points are awarded, read your instructor's Grading Policy [Return to Standard Assignment View] Canceling a Magnetic Field
More informationPhysics 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
More informationAmpere'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
More informationCathode Ray Tube. Introduction. Functional principle
Introduction The Cathode Ray Tube or Braun s Tube was invented by the German physicist Karl Ferdinand Braun in 897 and is today used in computer monitors, TV sets and oscilloscope tubes. The path of the
More informationLecture PowerPoints. Chapter 20 Physics: Principles with Applications, 7 th edition Giancoli
Lecture PowerPoints Chapter 20 Physics: Principles with Applications, 7 th edition Giancoli This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching
More information21 MAGNETIC FORCES AND MAGNETIC FIELDS
CHAPTER 21 MAGETIC ORCE AD MAGETIC IELD COCEPTUAL QUETIO 1. REAOIG AD OLUTIO Magnetic field lines, like electric field lines, never intersect. When a moving test charge is placed in a magnetic field so
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 informationThe Solar Wind. Earth s Magnetic Field p.1/15
The Solar Wind 1. The solar wind is a stream of charged particles  a plasma  from the upper atmosphere of the sun consisting of electrons and protons with energies of 1 kev. 2. The particles escape the
More informationExperiment 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 currentcarrying
More informationExperiment 3: Magnetic Fields of a Bar Magnet and Helmholtz Coil
MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Physics 8.02 Spring 2006 Experiment 3: Magnetic Fields of a Bar Magnet and Helmholtz Coil OBJECTIVES 1. To learn how to visualize magnetic field lines
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 informationCalculate the centripetal acceleration of the boot just before impact
(ii) alculate the centripetal acceleration of the boot just before impact....... (iii) iscuss briefly the radial force on the knee joint before impact and during the impact................. (4) (Total
More informationPhysics 42 Lab 4 Fall 2012 Cathode Ray Tube (CRT)
Physics 42 Lab 4 Fall 202 Cathode Ray Tube (CRT) PRELAB Read the background information in the lab below and then derive this formula for the deflection. D = LPV defl 2 SV accel () Redraw the diagram
More information2015 Pearson Education, Inc. Section 24.5 Magnetic Fields Exert Forces on Moving Charges
Section 24.5 Magnetic Fields Exert Forces on Moving Charges Magnetic Fields Sources of Magnetic Fields You already know that a moving charge is the creator of a magnetic field. Effects of Magnetic Fields
More informationDeflection of Electrons in an Electric Field
Name: Partners: Date: Deflection of Electrons in an Electric Field Purpose In this lab, we use a Cathode Ray Tube (CRT) to measure the effects of an electric field on the motion of a charged particle,
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 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 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 informationPhys 102 Spg Exam No. 2 Solutions
Phys 102 Spg. 2008 Exam No. 2 Solutions I. (20 pts) A 10turn wire loop measuring 8.0 cm by 16.0 cm carrying a current of 2.0 A lies in the horizontal plane and is free to rotate about a horizontal axis
More informationGraphical Presentation of Data
Graphical Presentation of Data Guidelines for Making Graphs Titles should tell the reader exactly what is graphed Remove stray lines, legends, points, and any other unintended additions by the computer
More informationMagnetic Forces and Magnetic Fields
1 Magnets Magnets are metallic objects, mostly made out of iron, which attract other iron containing objects (nails) etc. Magnets orient themselves in roughly a north  south direction if they are allowed
More informationPhysics Notes for Class 12 Chapter 4 Moving Charges and Magnetrism
1 P a g e Physics Notes for Class 12 Chapter 4 Moving Charges and Magnetrism Oersted s Experiment A magnetic field is produced in the surrounding of any current carrying conductor. The direction of this
More informationModule 3 : MAGNETIC FIELD Lecture 15 : Biot Savarts' Law
Module 3 : MAGNETIC FIELD Lecture 15 : Biot Savarts' Law Objectives In this lecture you will learn the following Study BiotSavart's law Calculate magnetic field of induction due to some simple current
More informationConceptual: 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 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 14: Magnets and Electromagnetism
Chapter 14: Magnets and Electromagnetism 1. Electrons flow around a circular wire loop in a horizontal plane, in a direction that is clockwise when viewed from above. This causes a magnetic field. Inside
More information(b) Draw the direction of for the (b) Draw the the direction of for the
2. An electric dipole consists of 2A. A magnetic dipole consists of a positive charge +Q at one end of a bar magnet with a north pole at one an insulating rod of length d and a end and a south pole at
More informationMechanics Lecture Notes. 1 Notes for lectures 12 and 13: Motion in a circle
Mechanics Lecture Notes Notes for lectures 2 and 3: Motion in a circle. Introduction The important result in this lecture concerns the force required to keep a particle moving on a circular path: if the
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 informationExperiment 3: Magnetic Fields of a Bar Magnet and Helmholtz Coil
MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Physics 8.02 Spring 2009 Experiment 3: Magnetic Fields of a Bar Magnet and Helmholtz Coil OBJECTIVES 1. To learn how to visualize magnetic field lines
More informationELECTRIC FIELD LINES AND EQUIPOTENTIAL SURFACES
ELECTRIC FIELD LINES AND EQUIPOTENTIAL SURFACES The purpose of this lab session is to experimentally investigate the relation between electric field lines of force and equipotential surfaces in two dimensions.
More informationFaraday s and Lenz s Law: Induction
Lab #18 Induction page 1 Faraday s and Lenz s Law: Induction Reading: Giambatista, Richardson, and Richardson Chapter 20 (20.120.9). Summary: In order for power stations to provide electrical current
More informationPROBLEM #8: DEFLECTION OF AN ELECTRON BEAM BY AN ELECTRIC FORCE
PROBLEM #8: DEFLECTION OF AN ELECTRON BEAM BY AN ELECTRIC FORCE You are investigating different methods of treating malignant skin tumors without surgery. One suggestion is to use high energy electrons
More informationCentripetal Force. 1. Introduction
1. Introduction Centripetal Force When an object travels in a circle, even at constant speed, it is undergoing acceleration. In this case the acceleration acts not to increase or decrease the magnitude
More informationObjectives for the standardized exam
III. ELECTRICITY AND MAGNETISM A. Electrostatics 1. Charge and Coulomb s Law a) Students should understand the concept of electric charge, so they can: (1) Describe the types of charge and the attraction
More information1. Separation is easy with a magnet (try it and be amazed!).
EXERCISES 1. Separation is easy with a magnet (try it and be amazed!). 2. All magnetism originates in moving electric charges. For an electron there is magnetism associated with its spin about its own
More informationJ.J. Thomson, Cathode Rays and the Electron
Introduction Voltage source Experimenters had noticed that sparks travel through rarefied (i.e. low pressure) air since the time of Franklin. The basic setup was to have two metal plates inside a glass
More informationLecture 5 Physics of Welding Arc I Keywords: 5.1 Introduction 5.2 Emission of Free electrons
Lecture 5 Physics of Welding Arc I This chapter presents fundamentals of welding arc, mechanisms of electron emission, different zones in welding arc, electrical aspects related with welding arc and their
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 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 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 informationEðlisfræði 2, vor 2007
[ Assignment View ] [ Pri Eðlisfræði 2, vor 2007 29a. Electromagnetic Induction Assignment is due at 2:00am on Wednesday, March 7, 2007 Credit for problems submitted late will decrease to 0% after the
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 informationLABORATORY V MAGNETIC FIELDS AND FORCES
LABORATORY V MAGNETIC FIELDS AND FORCES Magnetism plays a large part in our modern world's technology. Magnets are used today to image parts of the body, to explore the mysteries of the human brain, and
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 informationCentripetal Force. This result is independent of the size of r. A full circle has 2π rad, and 360 deg = 2π rad.
Centripetal Force 1 Introduction In classical mechanics, the dynamics of a point particle are described by Newton s 2nd law, F = m a, where F is the net force, m is the mass, and a is the acceleration.
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 information** Can skip to Problems: 6, 7, 9, 15, 19, 28, 29, 35, 36, 39, 42 **
Walker, Physics, 3 rd Edition Chapter 22 ** Can skip to Problems: 6, 7, 9, 15, 19, 28, 29, 35, 36, 39, 42 ** Conceptual Questions (Answers to oddnumbered Conceptual Questions can be found in the back
More informationPhysics 12 Study Guide: Electromagnetism Magnetic Forces & Induction. Text References. 5 th Ed. Giancolli Pg
Objectives: Text References 5 th Ed. Giancolli Pg. 58896 ELECTROMAGNETISM MAGNETIC FORCE AND FIELDS state the rules of magnetic interaction determine the direction of magnetic field lines use the right
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 informationRotational Motion. Description of the motion. is the relation between ω and the speed at which the body travels along the circular path.
Rotational Motion We are now going to study one of the most common types of motion, that of a body constrained to move on a circular path. Description of the motion Let s first consider only the description
More informationCircular Motion. We will deal with this in more detail in the Chapter on rotation!
Circular Motion I. Circular Motion and Polar Coordinates A. Consider the motion of ball on a circle from point A to point B as shown below. We could describe the path of the ball in Cartesian coordinates
More information5.Magnetic Fields due to Currents( with Answers)
5.Magnetic Fields due to Currents( with Answers) 1. Suitable units for µ. Ans: TmA 1 ( Recall magnetic field inside a solenoid is B= µ ni. B is in tesla, n in number of turn per metre, I is current in
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 informationHand Held Centripetal Force Kit
Hand Held Centripetal Force Kit PH110152 Experiment Guide Hand Held Centripetal Force Kit INTRODUCTION: This elegantly simple kit provides the necessary tools to discover properties of rotational dynamics.
More informationLab 7: Rotational Motion
Lab 7: Rotational Motion Equipment: DataStudio, rotary motion sensor mounted on 80 cm rod and heavy duty bench clamp (PASCO ME9472), string with loop at one end and small white bead at the other end (125
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 information