THE CHARGE-TO-MASS RATIO OF THE ELECTRON
|
|
- Jocelyn Watts
- 6 years ago
- Views:
Transcription
1 THE CHARGE-TO-MASS RATIO OF THE ELECTRON Is the beam that produces images on a cathode ray tube (CRT) television or computer monitor a beam of particles or of waves? This was a lively source of debate in the world of physics over one hundred years ago (long before there were televisions or computers). J. J. Thomson showed that this beam has particle like qualities in 1897, in an experiment which you will recreate today in class. LIBRARY WORK: The 1890s were a Golden Age for research on beams, with the discovery of X-rays and natural radioactivity, and intense research on the cathode rays which we will study in the laboratory. Find a description of J. J. Thomson's experiment. What exactly did he do? What is the physics behind what he did? What were the results of his work? For bonus points, what was his technological edge that allowed him to succeed before his rivals did? (An interesting line of beam-physics research that didn't pan out is the story of 'N-rays'. A good short introduction can be found in Ostdiek and Bord's Inquiry into Physics.) EXPERIMENT SETUP: There are four circuits that you need to connect in order to conduct this experiment. The filament circuit is a bit like a light bulb. You connect a 6 V RMS AC signal to a metal filament. The voltage heats up the filament and causes electrons to boil off. The next circuit is the accelerating circuit. This circuit applies a very high voltage which creates an electric field that accelerates the electrons across the tube. Finally we have two deflection circuits that cause the beam to bend in a direction perpendicular to the path of the beam. The first is an Electrostatic Deflection circuit. Here we apply a DC voltage between two plates creating an electric field that can be used to deflect the beam upwards or downwards. The second is a Magnetic Deflection circuit where Helmholz coils are used to generate a magnetic field. The magnetic field creates a force on the moving electrons in a direction perpendicular to the magnetic field and perpendicular to the motion of the electrons. The connection of each of these four circuits is described in the following sections. CAUTION: In this experiment you will be working with potential differences of up to 5000 volts. As in other electrical experiments, you should be careful to avoid any exposed leads. Make sure that no wires that connect to high voltages show any exposed metal that you might accidentally touch.
2 I. filament circuit 5 kv power supply III Deflection Circuit 5 kv power supply 0V 0V +5kV 0V 6V 12V +5kV 0V 6V 12V II Accelerating Circuit I. THE FILAMENT CIRCUIT (freeing the electrons): Connect the two sockets on the 'barrel end' of the tube to 6VAC from the 5kV power supply (yellow sockets). Check with your instructor to make sure you've done the right thing. Once you have consulted with the instructor, you may turn on the 5kV power supply. It is a good habit to always turn the voltage knob of any power supply (especially a high voltage one) all the way counterclockwise before turning it on. When you have turned on the power supply, there should be a white light glowing from the filament. If not, consult your instructor immediately. Turn the power supply off again. II. THE ACCELERATING CIRCUIT (forming the electrons into a beam): We haven't used the high voltage part of the power supply yet. Connect the leftmost 0V terminal of the high-voltage power supply ( ) to either of the two sockets on the barrel end of the tube or to one of the terminals to which they are connected. Connect the rightmost red 5kV terminal to the metal pin sticking out of the side of the tube. To maximize your peace of mind, you should choose a wire that doesn't leave any metal exposed at this connection. Now connect either this side terminal or the (+) terminal of the power supply to the ground terminal of the power supply. Do NOT turn on the power supply until your instructor has checked your circuit. Then turn it on, providing current to the filament, and increase the accelerating voltage slowly from zero until you see a blue line glowing on the paper grid in your tube. This is an electron beam. It should come on well before you hit 4kV. If not, don't panic: call your instructor. 2
3 III. ELECTROSTATIC DEFLECTION: Using a second 5kV power supply, put a voltage across the two deflecting plates. Make sure that one of them is connected to the ground terminal of the first 5kV power supply, as in the diagram. Once again, choose your wires so as to avoid exposed leads! Keeping the accelerating voltage constant, observe what happens when this deflection voltage is varied. The electrons can be shown to follow a parabola governed by the following equation y = e 2m E x 2 (1) v where E is the electric field, m is the mass of the particle, v is the velocity of the particle, and x and y are the position coordinates of the parabola. IV. THE MAGNETIC FIELD CIRCUIT: There are two Helmholtz coils, each with a terminal labeled A and a terminal labeled Z. Anchor the coils into the stand, with each one cradling the spherical end of the e/m tube. Connect the two Z terminals together, and connect the output Ammeter of the adjustable 30V DC power supply to the terminal labeled A. Connect a DC ammeter in series with one of the power supply leads going to one of the A terminals. A Z power supply Z A 6 V ELECTROMAGNETIC DEFLECTION: When an electron of charge e, moving with a velocity, v, is placed in a uniform magnetic field, B, it experiences a force due to the Lorentz Force F = q v X B (2) From Newton s second Law we know that F=ma, where m is the mass of the particle and a is its acceleration. Since the force is a result of a cross product, the direction of the force will be perpendicular to both the magnetic field and the velocity of the electron. When a force is perpendicular to a velocity, circular motion with a radius r, results, and the acceleration is the centripetal acceleration. Putting these ideas together gives us the following equation 3
4 F= q v X B = ma = mv 2 /r Bev = mv2 r (3) Turn on the power supply to the Helmholtz coils. Answer the following: a) For a fixed accelerating voltage, V a, describe how the radius of the electron's orbit changes with I B, the current in the Helmholtz coil? b) How can you change the velocity of the electrons? Describe the effect this has on the radius? DETERMINATION OF e/m BY THOMSON'S METHOD: Thomson showed that if an electrical field of strength E is applied at the same time as, and perpendicular to, an electromagnetic field B, so that the two deflections are in the same plane but opposite directions, these can be balanced by adjustment of the fields so that F E =F B ee=bev Now we can solve for the velocity of the electrons v = E/B. (4) Turn the current through the Helmholtz coils back on and establish the condition of balance (no deflection) by varying the current, I B in the Helmholtz coils with a fixed V P between the deflecting plates. Can you find a setting for voltage and current that gives a straight beam? What factors might be responsible for the curvature of the beam? Once Thomson knew the speed of the electron, he was able to find their charge to mass ratio by applying a magnetic deflection and using equation (3) DETERMINATION OF e/m BY ELECTROMAGNETIC DEFLECTION: More precise measurements of e/m can be made by assuming that the velocity of the electrons is governed by the 'gun' equation ev a = 1/2 mv 2 (5) together with measurements made when the electrons are deflected by the magnetic field alone. In the above equation the kinetic energy of the electrons is equal to the potential energy of the accelerating voltage. The above equation assumes no relativity. For what values of V a is that assumption justified? 4
5 Combining equations (3) and (5) gives e m = 2V a B 2 r (6) 2 You can find the radius r of the curve if you know the position of two points on the curve (x,y). The screen on our apparatus is tilted at an angle so that the beam of electrons hits the screen. For circles passing through the origin (the exit aperture of the anode) and the points (x,±y), we find the following relationship between r, x and y: r = ( x 2 cos y 2 ) /2y (7) DATA COLLECTION: Part I 1. Turn on the power supply providing filament current and accelerating potential, and turn up the high voltage until you get a faint beam. Adjust the position of the tube until the beam is as straight as possible. 2. Set the accelerating potential to 2000 volts, and adjust the output voltage of the power supply connected to the Helmholtz coils so that the center of the beam passes through the point (x=10cm, y=2cm) on the luminescent screen. Record the current in the Helmholtz coils. 3. Repeat step 2 for a total of at least five accelerating potentials. 4. Turn down and then turn off the Helmholtz coil power supply and interchange the leads supplying current to the Helmholtz coils so that the direction of the magnetic field will be reversed. 5. Turn on the power supplies and repeat steps 2 and 3 for the point (x=10cm, y=- 2cm) on the luminescent screen. Part II 1. Calibrate your Helmholtz coils by finding the magnetic-field-to-current ratio, B/I. The instructor will have a calibrated magnetic field sensor. Carefully remove your e/m tube from its stand and put it back in its box. Send at least five different values of current through your coils, measuring the range of magnetic field values inside the volume of the coils. Calculate the B/I ratio (with uncertainty!) which you will need for converting I's to B's later. (Use a graph!) 5
6 ANALYSIS 1. Using the average value of Helmholtz current for each accelerating potential above, calculate the magnetic field at each accelerating potential. 2. Compute a value for e/m at each accelerating potential. Compare your average value to the accepted value. 3. The equation for electromagnetic deflection (equation 3 above) can be rearranged to become: V a = e r2 B 2 2 m Plot V a on the y-axis and r2 B 2 along the x-axis. From the slope of the graph, find 2 an experimental value of e/m with uncertainty. Your actual uncertainty depends on other uncertainties in your experiment. Calculate it and compare your final results with the accepted value of e/m. 6
B = 8 0 NI/[r (5) 3/2 ],
ELECTRON BEAM IN A MAGNETIC FIELD Introduction: A charged body moving relative to a magnetic field experiences a force which is perpendicular to both the velocity of the particle and to the magnetic field.
More informationMAGNETIC DEFLECTION. OBJECTIVE: To observe the effect of a magnetic field on an electron beam. To measure the Earth s magnetic field.
MAGNETIC DEFLECTION OBJECTIVE: To observe the effect of a magnetic field on an electron beam. To measure the Earth s magnetic field. THEORY: Moving charges exert forces on one another that are not observed
More informationLaboratory 14: Ratio of Charge to Mass for the Electron
Laboratory 14: Ratio of Charge to Mass for the Electron Introduction The discovery of the electron as a discrete particle of electricity is generally credited to the British physicist Sir J. J. Thomson
More informationCHARGED PARTICLES IN FIELDS
The electron beam used to study motion of charged particles in electric and/or magnetic fields. CHARGED PARTICLES IN FIELDS Physics 41/61 Fall 01 1 Introduction The precise control of charged particles
More informationMAGNETIC DEFLECTION. OBJECTIVE: To observe the effect of a magnetic field on an electron beam. To measure the Earth s magnetic field.
MAGNETIC DEFLECTION OBJECTIVE: To observe the effect of a magnetic field on an electron beam. To measure the Earth s magnetic field. THEORY: Moving charges exert forces on one another that are not observed
More informationThis lab was adapted from Kwantlen University College s Determination of e/m lab.
e /m: Charge to Mass Ratio of the Electron This lab was adapted from Kwantlen University College s Determination of e/m lab. Purpose To determine the charge to mass ratio of the electron, e /m, using Helmholtz
More informationCharge to Mass Ratio of The Electron
Introduction Charge to Mass Ratio of The Electron The electron was first discovered by Sir J.J. Thomson in 1897 at the Cavendish Laboratory in Cambridge, England. His experimental apparatus is not very
More informationRatio of Charge to Mass (e/m) for the Electron
Objective: In this experiment you will determine the ratio of charge to mass (e/m) of the electron, by measuring the deflecting of electrons as they move through a magnetic field. Apparatus: e/m apparatus
More informationDetermining the Charge to Mass Ratio (e/m) for an Electron
Determining the Charge to Mass Ratio (e/m) for an Electron Introduction In order to determine the charge to mass ratio (e/m) for an electron we create a beam of electrons by heating a metal filament in
More informationBrown University PHYS 0060 Physics Department LAB B -190
Physics Department LAB B -190 THE FORCE OF A MAGNETIC FIELD ON A MOVING ELECTRIC CHARGE DETERMINATION OF THE RATIO OF CHARGE TO MASS, e/m, FOR ELECTRONS References: H.D. Young, University Physics, Eleventh
More informationMeasurement 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
More informationFinding e/m. Purpose. The purpose of this lab is to determine the charge to mass ratio of the electron. Equipment
Finding e/m Purpose The purpose of this lab is to determine the charge to mass ratio of the electron. Equipment Pasco Model SE-9638 E/M Apparatus Digital Multi-Meter, DMM Power Supply, Elenco Lead, Banana/Banana
More informationCharge to Mass Ratio of The Electron
Physics Topics Charge to Mass Ratio of The Electron If necessary, review the following topics and relevant textbook sections from Serway / Jewett Physics for Scientists and Engineers, 9th Ed. Electric
More informationMAGNETIC DEFLECTION. OBJECTIVE: To observe the effect of a magnetic field on an electron beam. To measure the Earth s magnetic field.
MAGNETIC DEFLECTION OBJECTIVE: To observe the effect of a magnetic field on an electron beam. To measure the Earth s magnetic field. THEORY: Moving charges exert forces on one another that are not observed
More informationLab 7 - ELECTRON CHARGE-TO-MASS RATIO
107 Name Date Partners Lab 7 - ELECTRON CHARGE-TO-MASS RATIO OBJECTIVES To understand how electric and magnetic fields impact an electron beam To experimentally determine the electron charge-to-mass ratio
More informationLab 1: Determination of e/m for the electron
Lab 1: Determination of e/m for the electron Background Reading: Tipler, Llewellyn pp. 125 130; this covers the original method of Thomson which is somewhat different from that used in this experiment
More informationCharge to Mass Ratio of Electron Lab 11 SAFETY
HB 10-20-08 Charge to Mass Ratio of Electron Lab 11 1 Charge to Mass Ratio of Electron Lab 11 Equipment ELWE e/m tube, ELWE Helmholtz coils, ELWE 4 voltage power supply, Safety Glasses, Fluke multimeter,
More informationTHE CHARGE-TO-MASS RATIO OF THE ELECTRON (e/m)
THE CHARGE-TO-MASS RATIO OF THE ELECTRON (e/m) INTRODUCTION In this experiment you will be measuring the charge to mass ratio, e/m, of the electron. The h/e apparatus consists of an electron gun, a helium
More informationLab 6 - Electron Charge-To-Mass Ratio
Lab 6 Electron Charge-To-Mass Ratio L6-1 Name Date Partners Lab 6 - Electron Charge-To-Mass Ratio OBJECTIVES To understand how electric and magnetic fields impact an electron beam To experimentally determine
More informationRatio of Charge to Mass for the Electron
Ratio of Charge to Mass for the Electron For a positive charge moving in a uniform magnetic field B with velocity v, the force F on the charge is always perpendicular to the magnetic field and the velocity.
More informationLab 5 - ELECTRON CHARGE-TO-MASS RATIO
79 Name Date Partners OBJECTIVES OVERVIEW Lab 5 - ELECTRON CHARGE-TO-MASS RATIO To understand how electric and magnetic fields impact an electron beam To experimentally determine the electron charge-to-mass
More informationLab 5 - ELECTRON CHARGE-TO-MASS RATIO
81 Name Date Partners Lab 5 - ELECTRON CHARGE-TO-MASS RATIO OBJECTIVES To understand how electric and magnetic fields impact an electron beam To experimentally determine the electron charge-to-mass ratio
More informationCHARGE TO MASS RATIO FOR THE ELECTRON
CHARGE TO MASS RATIO FOR THE ELECTRON OBJECTIVE: To measure the ratio of the charge of an electron to its mass. METHOD: A stream of electrons is accelerated by having them "fall" through a measured potential
More informationLab 6 - ELECTRON CHARGE-TO-MASS RATIO
101 Name Date Partners OBJECTIVES OVERVIEW Lab 6 - ELECTRON CHARGE-TO-MASS RATIO To understand how electric and magnetic fields impact an electron beam To experimentally determine the electron charge-to-mass
More informationExperiment V Motion of electrons in magnetic field and measurement of e/m
Experiment V Motion of electrons in magnetic field and measurement of e/m In Experiment IV you observed the quantization of charge on a microscopic bead and measured the charge on a single electron. In
More informationPhysicsAndMathsTutor.com 1
PhysicsAndMathsTutor.com 1 1. Millikan determined the charge on individual oil droplets using an arrangement as represented in the diagram. The plate voltage necessary to hold a charged droplet stationary
More informationThe e/m Ratio of the Electron
OBJECTIVE The e/m Ratio of the Electron To study the behavior of a charged particle in the presence of a potential difference. To study the behavior of a charged particle moving in a magnetic field. To
More informationChapter 1 The discovery of the electron 1.1 Thermionic emission of electrons
Chapter 1 The discovery of the electron 1.1 Thermionic emission of electrons Learning objectives: What are cathode rays and how were they discovered? Why does the gas in a discharge tube emit light of
More informationDeflection of Electrons
Deflection of Electrons Every statement in physics has to state relations between observable quantities. E. Mach (1838-1916) OBJECTIVES To determine the effect of electric and magnetic fields on a beam
More informationExperiment 2 Deflection of Electrons
Name Partner(s): Experiment 2 Deflection of Electrons Objectives Equipment Preparation Pre-Lab To study the effects of electric fields on beams of fast moving electrons. Cathode-ray tube (CRT), voltage
More informationExperiment 1 1. Charge- to- Mass Ratio of the Electron Physics 2150 Experiment No. 1 University of Colorado
Experiment 1 1 Introduction Charge- to- Mass Ratio of the Electron Physics 2150 Experiment No. 1 University of Colorado Both the charge and the mass of the electron are fundamental constants of considerable
More informationPre Lab for Ratio of Mass to. Charge of an Electron
Pre Lab for Ratio of Mass to Charge of an Electron The direction of the magnetic force on a charged particle moving in the magnetic field is given by the right hand rule. Students need practice using the
More informationHomework 2: Forces on Charged Particles
Homework 2: Forces on Charged Particles 1. In the arrangement shown below, 2 C of positive charge is moved from plate S, which is at a potential of 250 V, to plate T, which is at a potential of 750 V.
More informationMagnetic Deflection of Electrons
Magnetic Deflection of Electrons Objective Materials 1. Banana leads 2. Cathode ray tube 3. Fisher 1V/30V power supply (set to 30V) 4. Fluke digital multimeter 5. High voltage power supply 6. Solenoid
More informationLab in a Box Measuring the e/m ratio
Safety Precautions All the signal voltages are small and harmless. The mains voltages in the mains powered equipment is dangerous but is screened in normal use. The fine beam tube requires dangerous contact
More informationPHY222 Lab 8 - Magnetic Fields and Right Hand Rules Magnetic forces on wires, electron beams, coils; direction of magnetic field in a coil
PHY222 Lab 8 - 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 informationInstruction Manual. from. Seventh Edition. These Manual pages reprinted with kind permission.
Instruction Manual from PSSC Physics Laboratory Guide Seventh Edition These Manual pages reprinted with kind permission. From the Laboratory Guide. PSSC Physics, Seventh Edition, by Haber-Schaim. Dodge.
More informationYou should be able to demonstrate and show your understanding of:
OCR B Physics H557 Module 6: Field and Particle Physics You should be able to demonstrate and show your understanding of: 6.1: Fields (Charge and Field) Field: A potential gradient Field Strength: Indicates
More informationCharge to Mass Ratio of the Electron
Charge to Mass Ratio of the Electron 1. Purpose: To determine the charge to mass ratio of the electron, e/m, by subjecting a beam of electrons to a magnetic field and examining their trajectories. It can
More informationExperiment 5 Deflection of Electrons
Experiment 5 Deflection of Electrons Every statement in physics has to state relations between observable quantities. E. Mach OBJECTIVES To determine the effect of electric and magnetic fields on a beam
More informationElectron charge-to-mass ratio
(ta initials) first name (print) last name (print) brock id (ab17cd) (lab date) Experiment 4 Electron charge-to-mass ratio In this Experiment you will learn the relationship between electric and magnetic
More informationThe Measurement of e/m
MSCD/UCD Physics Laboratories Lab II e/m The Measurement of e/m PURPOSE The objectives of this experiment are to measure the ratio between the charge and the mass of electrons, and then to find the mass
More informationKE = 1 2 mv2 = ev. (1)
The e/m ratio Objective To measure the electronic charge-to-mass ratio e/m, by injecting electrons into a magnetic field and examining their trajectories. We also estimate the magnitude of the earth s
More informationExperiment 4: Charge to mass ratio (e/m) of the electron
Experiment 4: Charge to mass ratio (e/m) of the electron Nate Saffold nas2173@columbia.edu Office Hour: Monday, 5:30PM-6:30PM @ Pupin 1216 INTRO TO EXPERIMENTAL PHYS-LAB 1494/2699 Introduction Our first
More informationMEASUREMENT OF THE CHARGE TO MASS RATIO (e/m e ) OF AN ELECTRON
MEASUREMENT OF THE CHARGE TO MASS RATIO (e/m e ) OF AN ELECTRON Object This experiment will allow you to observe and understand the motion of a charged particle in a magnetic field and to measure the ratio
More informationEXPERIMENT 2-6. e/m OF THE ELECTRON GENERAL DISCUSSION
Columbia Physics: Lab -6 (ver. 10) 1 EXPERMENT -6 e/m OF THE ELECTRON GENERAL DSCUSSON The "discovery" of the electron by J. J. Thomson in 1897 refers to the experiment in which it was shown that "cathode
More informationCharge-to-mass ratio for the electron
Charge-to-mass ratio for the electron Introduction This is a variation of the original experiment carried out by J.J.Thomson in 1895. The deflection of a charge moving in a magnetic field is clearly demonstrated.
More informationThe Ratio of Charge to Mass (e/m) for an Electron
The Ratio of Charge to Mass (e/m) for an Electron OBJECT: The object of this experiment is to determine the ratio of charge to mass (e/m) for an electron and compare it with its theoretical value. THEORY:
More informationInstruction Manual for EP-20 e/m of the Electron Apparatus
Instruction Manual for EP-20 e/m of the Electron Apparatus Introduction This self-contained apparatus is designed for the measurement of e/m of the electron by observing the radius of the circular path
More informationMAGNETISM LAB: The Charge-to-Mass Ratio of the Electron
Physics 7B Charge-to-mass: e/m p. 1 NAME: DL SECTION NUMBER: GSI: LAB PARTNERS: MAGNETISM LAB: The Charge-to-Mass Ratio of the Electron Introduction In this lab you will explore the motion of a charged
More informationElectric Deflection of Electrons
Electric Deflection of Electrons Objective The purpose of this experiment is to observe that the spacial deflection of an electron in a cathode ray tube is directly proportional to the deflection potential.
More informationExperiment 7: The Electron s Charge to Mass Ratio
Chapter 9 Experiment 7: The Electron s Charge to Mass Ratio 9.1 Introduction Historical Aside Benjamin Franklin suggested that all matter was made of positively and negatively charged fluids that flowed
More informationv = E B FXA 2008 UNIT G485 Module Magnetic Fields BQv = EQ THE MASS SPECTROMETER
UNIT G485 Module 1 5.1.2 Magnetic Fields 11 Thus, in order for the particle to suffer NO DEFLECTION and so exit the device at Y : From which : MAGNETIC FORCE UP = ELECTRIC FORCE DOWN BQv = EQ THE MASS
More informationExperiment 2-3. What s Happening Between Currents? -Lorenz Force-
Experiment 2-3. What s Happening Between Currents? -Lorenz Force- Purpose of Experiment A current-carrying electric wire produces a magnetic field. When a closed current-carrying wire is placed in a magnetic
More informatione/m APPARATUS Instruction Manual and Experiment Guide for the PASCO scientific Model SE D 5/ PASCO scientific $5.
Includes Teacher's Notes and Typical Experiment Results Instruction Manual and Experiment Guide for the PASCO scientific Model SE9638 020347D 5/94 e/m APPARATUS 987 PASCO scientific $5.00 020347D e/m
More information3B SCIENTIFIC PHYSICS
B SCIENTIFIC PHYSICS ElectronBeam Deflection Tube D 6 Instruction sheet / LF 9 8 7 6 7 6 Fluorescent screen Lower deflection plate Boss with mm plug for connecting deflection plates Electron gun mm sockets
More informationMEASUREMENT OF THE CHARGE TO MASS RATIO (e/m e ) OF AN ELECTRON
MEASUREMENT OF THE CHARGE TO MASS RATIO (e/m e ) OF AN ELECTRON Object This experiment will allow you to observe and understand the motion of a charged particle in a magnetic field and to measure the ratio
More informationPhysicsAndMathsTutor.com 1
PhysicsAndMathsTutor.com 1 Q1. (a) The diagram below shows a narrow beam of electrons produced by attracting electrons emitted from a filament wire to a metal plate which has a small hole in it. (i) Why
More informationDiffraction of Electrons
Diffraction of Electrons Object: Apparatus: Verify that electrons are waves; i.e., that they diffract just like light waves. This lab is then used to measure their wavelength or, alternatively, measure
More informationEXPERIMENT NO. 2. Electrostatic and Magnetic Deflection of Electrons in a Cathode Ray Tube
EXPERIMENT NO. Electrostatic and Magnetic Deflection of Electrons in a Cathode Ray Tube Part A. Motion of electrons in an electric field: Introduction The heart of an oscilloscope is the cathode-ray tube
More informationChapter 12. Project 4 Classical Physics. Experiment A: The Charge to Mass Ratio of the Electron
Chapter 12 Project 4 Classical Physics Experiment A: The Charge to Mass Ratio of the Electron 12A.1 Objectives (a) To perform Lenard's classic experiment to determine e/m. (b) To evaluate the ratio e/m
More informationElectron Diffraction
Electron iffraction o 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 de
More informationMass of the Electron
PHY 192 Charge and Mass of the Electron Spring 2013 1 Mass of the Electron Motivation for the Experiment The aim of this experiment is to measure the mass of the electron. The mass will be deduced from
More informationElectrostatic and Magnetic Deflection of Electrons in a Cathode Ray Tube
Electrostatic and Magnetic Deflection of Electrons in a Cathode Ray Tube Andy Chmilenko, 0310799 Instructor: Tan Dinh Section 1 (Dated: :30 pm Wednesday May 9, 013) I. PURPOSE The purpose of this experiment
More information1 Written and composed by: Prof. Muhammad Ali Malik (M. Phil. Physics), Govt. Degree College, Naushera
ELECTROMAGNETISM Q # 1. Describe the properties of magnetic field due to current in a long straight conductor. Ans. When the heavy current is passed through a straight conductor: i. A magnetic field is
More informationE/M. Hunter Layman Bridgewater College 1/16/2016
E/M Hunter Layman Bridgewater College 1/16/016 Abstract The charge to mass ratio of an electron was observed in the experiment. This experiment involved the use of a PASCO scientific Model SE 9638 e/m
More informationChapter 23 Electric Potential. Copyright 2009 Pearson Education, Inc.
Chapter 23 Electric Potential Units of Chapter 23 Electric Potential Energy and Potential Difference Relation between Electric Potential and Electric Field Electric Potential Due to Point Charges Potential
More information1 P a g e h t t p s : / / w w w. c i e n o t e s. c o m / Physics (A-level)
1 P a g e h t t p s : / / w w w. c i e n o t e s. c o m / Capacitance (Chapter 18): Physics (A-level) Every capacitor has two leads, each connected to a metal plate, where in between there is an insulating
More informationEvery magnet has a north pole and south pole.
Magnets - Intro The lodestone is a naturally occurring mineral called magnetite. It was found to attract certain pieces of metal. o one knew why. ome early Greek philosophers thought the lodestone had
More informationPHYSICS 12 NAME: Electrostatics Review
NAME: Electrostatics Review 1. An electron orbits a nucleus which carries a charge of +9.6 x10-19 C. If the electron s orbital radius is 2.0 x10-10 m, what is its electric potential energy? A. -6.9 x10-18
More informationCharge to mass Ratio. Nature of the Atom: Dalton's Contributions to Science. 6) qm ratio notes.notebook. December 13, 2018
Nature of the Atom: Charge to mass Ratio Studies of atoms from John Dalton's atmospheric studies indicated that properties were cyclic moving from group to group. This suggested some unit of atomic structure
More informationPHYS 1102 EXAM - II. SECTION: (Circle one) 001 (TH 9:30 AM to 10:45AM) 002 (TH 3:30 PM to 4:45 PM) You have 1 hr 45 minutes to complete the test
PHYS 1102 EXAM - II SECTION: (Circle one) 001 (TH 9:30 AM to 10:45AM) 002 (TH 3:30 PM to 4:45 PM) Your Name: Student ID: You have 1 hr 45 minutes to complete the test PLEASE DO NOT START TILL YOU ARE INSTRUCTED
More informationPHYSICS 12 NAME: Magnetic Field and Force
NAME: Magnetic Field and Force 1. An aircraft whose wingspan is 15 m carries a static charge of 0.60 C. It travels at 240 m/s perpendicular to a 1.5x10-4 T magnetic field. What magnetic force does the
More informationChapter 12. Magnetism and Electromagnetism
Chapter 12 Magnetism and Electromagnetism 167 168 AP Physics Multiple Choice Practice Magnetism and Electromagnetism SECTION A Magnetostatics 1. Four infinitely long wires are arranged as shown in the
More information2R R R 2R. Phys Test 1
Group test. You want to calculate the electric field at position (x o, 0, z o ) due to a charged ring. The ring is centered at the origin, and lies on the xy plane. ts radius is and its charge density
More informationChapter 17 Electric Potential
Chapter 17 Electric Potential Units of Chapter 17 Electric Potential Energy and Potential Difference Relation between Electric Potential and Electric Field Equipotential Lines The Electron Volt, a Unit
More informationMagnetostatics. P.Ravindran, PHY041: Electricity & Magnetism 22 January 2013: Magntostatics
Magnetostatics Magnetic Fields We saw last lecture that some substances, particularly iron, possess a property we call magnetism that exerts forces on other magnetic materials We also saw that t single
More informationPHYSICS 3204 PUBLIC EXAM QUESTIONS (Magnetism &Electromagnetism)
PHYSICS 3204 PUBLIC EXAM QUESTIONS (Magnetism &Electromagnetism) NAME: August 2009---------------------------------------------------------------------------------------------------------------------------------
More informationMagnetism Chapter Questions
Magnetism Chapter Questions 1. Both Electric and Magnetic Forces will cause objects to repel and attract each other. What is a difference in the origin of these forces? 2. A Magnet has a north and a south
More informationOther Formulae for Electromagnetism. Biot's Law Force on moving charges
Other Formulae for Electromagnetism Biot's Law Force on moving charges 1 Biot's Law. Biot's Law states that the magnetic field strength (B) is directly proportional to the current in a straight conductor,
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 informationSpring Not-Break Review Assignment
Name AP Physics B Spring Not-Break Review Assignment Date Mrs. Kelly. A kilogram block is released from rest at the top of a curved incline in the shape of a quarter of a circle of radius R. The block
More information1. Draw in the magnetic field inside each box that would be capable of deflecting the particle along the path shown in each diagram.
Charged Particles in Magnetic Fields 1. Draw in the magnetic field inside each box that would be capable of deflecting the particle along the path shown in each diagram. a b c d 2. a. Three particles with
More informationDownloaded from
Question 4.1: A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. What is the magnitude of the magnetic field B at the centre of the coil? Number of turns
More informationLab 7: Magnetic fields and forces Lab Worksheet
Lab 7: Magnetic fields and forces Lab Worksheet Name This sheet is the lab document your TA will use to score your lab. It is to be turned in at the end of lab. To receive full credit you must use complete
More informationAP Physics Electromagnetic Wrap Up
AP Physics Electromagnetic Wrap Up Here are the glorious equations for this wonderful section. This is the equation for the magnetic force acting on a moving charged particle in a magnetic field. The angle
More informationEnd-of-Chapter Exercises
End-of-Chapter Exercises Exercises 1 12 are primarily conceptual questions designed to see whether you understand the main concepts of the chapter. 1. (a) If the electric field at a particular point is
More informationCURRENT-CARRYING CONDUCTORS / MOVING CHARGES / CHARGED PARTICLES IN CIRCULAR ORBITS
PHYSICS A2 UNIT 4 SECTION 4: MAGNETIC FIELDS CURRENT-CARRYING CONDUCTORS / MOVING CHARGES / CHARGED PARTICLES IN CIRCULAR ORBITS # Questions MAGNETIC FLUX DENSITY 1 What is a magnetic field? A region in
More informationPHYSICS 30 ELECTROMAGNETISM ASSIGNMENT 3 VERSION:0
Communication includes statement of the physics concept used and how it is applied in the situation along with diagrams, word explanations and calculations in a well laid out formula, substitution, answer
More informationChapter 17: Magnetism
Chapter 17: Magnetism Section 17.1: The Magnetic Interaction Things You Already Know Magnets can attract or repel Magnets stick to some things, but not all things Magnets are dipoles: north and south Labels
More informationCh 17 Problem Set 31. A toaster is rated at 600 W when connected to a 120-V source. What current does the toaster carry, and what is its resistance?
Ch 17 Problem Set 31. A toaster is rated at 600 W when connected to a 120-V source. What current does the toaster carry, and what is its resistance? 33. How many 100-W lightbulbs can you use in a 120-V
More informationChapter 28. Magnetic Fields. Copyright 2014 John Wiley & Sons, Inc. All rights reserved.
Chapter 28 Magnetic Fields Copyright 28-1 Magnetic Fields and the Definition of B The Definition of B The Field. We can define a magnetic field B to be a vector quantity that exists when it exerts a force
More informationTIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES. PHYS 1112, Exam 2 Section 1 Version 1 April 2, 2013 Total Weight: 100 points
TIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES PHYS 1112, Exam 2 Section 1 Version 1 April 2, 2013 Total Weight: 100 points 1. Check your examination for completeness prior to starting.
More informationPHYSICS ORDINARY LEVEL
*B16* PRE-LEAVING CERTIFICATE EXAMINATION, 2011 PHYSICS ORDINARY LEVEL TIME: 3 HOURS Answer three questions from section A and five questions from section B. Page 1 of 10 SECTION A (120 marks) Answer three
More informationUniversity of Massachusetts, Amherst
PHYSICS 286: Modern Physics Laboratory SPRING 2010 (A. Dinsmore and K. Kumar) Feb 2009 Experiment 4: THE FRANCK HERTZ EXPERIMENT Electronic Excitations of a Gas, and Evidence for the Quantization of Atomic
More informationChapter 27 Magnetism 1/20/ Magnets and Magnetic Fields Magnets and Magnetic Fields Magnets and Magnetic Fields
Chapter 27 Magnetism Magnets have two ends poles called north and south. Like poles repel; unlike poles attract. However, if you cut a magnet in half, you don t get a north pole and a south pole you get
More informationFig. 2.1 I =... A [2] Suggest why it would be impossible for overhead cables carrying an alternating current to float in the Earth s magnetic field.
1 (a) Fig. 2.1 shows a horizontal current-carrying wire placed in a uniform magnetic field. I region of uniform magnetic field wire Fig. 2.1 The magnetic field of flux density 0.070 T is at right angles
More informationSection 11: Magnetic Fields and Induction (Faraday's Discovery)
Section 11: Magnetic Fields and Induction (Faraday's Discovery) In this lesson you will describe Faraday's law of electromagnetic induction and tell how it complements Oersted's Principle express an understanding
More informationAdvanced Higher Physics. Electromagnetism
Wallace Hall Academy Physics Department Advanced Higher Physics Electromagnetism Problems AH Physics: Electromagnetism 1 2013 Data Common Physical Quantities QUANTITY SYMBOL VALUE Gravitational acceleration
More informationAP Physics Study Guide Chapter 17 Electric Potential and Energy Name. Circle the vector quantities below and underline the scalar quantities below
AP Physics Study Guide Chapter 17 Electric Potential and Energy Name Circle the vector quantities below and underline the scalar quantities below electric potential electric field electric potential energy
More information