H int h ow can you m ake a qualitative prediction w

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Unformatted text preview: es, equations, d raw ings, and / or graphs, m ake a clear and concise pred iction that solves the task. (H int: H ow can you m ake a qualitative prediction w ith as m uch d etail as possible?) EXPLORATION System atically construct an electric field m ap using EM Field program . For instructions o n how to use this program see the Exploration section of the “Electric Field Vectors” lab problem . Save your result to pd f. N ext, construct a physical m od el of a d ipole using the battery, rod s, and cond uctive paper. Make sure to read the suggested append ix m aterials for d etails on how to use the D MM and the cond uctive paper setup. Follow the instructions given there to set up the cond uctive paper. 16 ELECTRIC FIELD FROM A DIPOLE – 1302Lab1Prob2 O nce the rod s are connected to the battery, set the d igital m ultimeter (DMM) to DC volts and turn it on . Place the tip s of the probe on the cond uctive paper m id w ay betw een the tips of th e tw o rod s. Ad just the units on the DMM until you obtain reasonable read ings. Recall the field m aps you generated in the w arm up questions and w ith EM Field . Rotate the probe so that the center of the probe stays in the sam e spot. D o the values change (pay attention to the sign)? Is there a m inim um or m axim um value as you rotate the probe? Are there any apparent sym m etries as you rotate the probe? If there are large fluctuations in the read ings, d eterm ine how you w ill m easure consistently. Determ ine how you w ill use the probe to d eterm ine the electric field direction a t other points. N ow place the field probe near, but not touching, one of the rod s and rotate the probe as you d id before. Record your d ata. Determ ine the d irection of the electric field . Com pare the m axim um DMM read ing at this point to the one you found at the m id w ay point. Com pare your m easurem ents to your pred iction; d oes the value d isplayed on the DMM becom e larger or sm aller w hen the electric field becom es stronger? Consid er how you w ill use the probe to d eterm ine the electric field s trength a t other points. Test a few m ore key points on the cond uctive paper. Where on the cond uctive paper is the electric field strongest? Weakest? Consid er w hether your observations m atch your pred ictions. Discuss in your group how you w ill use the probe to d eterm ine the field s trength a nd d irection a t an arbitrary point on the cond uctive paper and how you w ill record the results on the w hite copy of the cond uctive paper. Discu ss how you could construct a system atic m ap (hint: think grid ) of the d ipole’s electric field . M EASUREMEN T C om plete your m easurem ent plan for m apping the electric field on the cond uctive paper. Select a point on the cond u ctive paper w here you w ish to d eterm ine the electric field and d eterm ine its m agnitude a nd d irection . Repeat the m easurem ent to gain an estim ate of the m easurem ent uncertainty. Record the result on the w hite copy of the cond uctive paper. Repeat for as m any points as need ed to system atically create a field m ap that can be used to check your pred iction. IMPORTAN T: Dissem inate electronic copies of your results from this and exploration section to each m em ber of your group. Your TA can provid e you w ith scans of your hand -constructed d ipole m ap, or you m ay scan it on your ow n tim e after lab. A N ALYSIS AN D CON CLUSION H ow d oes your m ap com pare to your pred iction? H ow d oes it com pare to the sim ulation program ? Where is the field strongest? H ow d o you show this in your 17 ELECTRIC FIELD FROM A DIPOLE – 1302Lab1Prob2 m ap? Where is the field w eakest? H ow d o you show this in your m ap? Do your answ ers som ehow d ep end on the axis of sym m etry und er consid eration? Overall, w as your pred iction successful? Why or w hy not? 18 PROBLEM #3: GRAVITATION AL FORCE ON THE ELECTRON You w ork in a research laboratory that is attem pting to m ake a better electron m icroscope. The project requires precise control of a beam of electrons. To stud y your ability to m anipulate electron m otion, you d ecid e to use a Cathod e Ray Tube (CRT) (the sam e d evice that is the basis of old er, box-style TV sets. In the CRT, electrons are em itted at one end of an evacuated glass tube (called the cathod e) and are d etected by their interaction w ith a phosphorous screen on the other end (called the anod e). Every object near the Earth's surface is subject to the gravitational force. Your team -m ates are w orried that the gravitational force w ill d eflect the electron from the d esired path, and that this d eflection w ill d epend on w hether the beam is vertical or ho rizontal (or at som e general angle of inclination). From your physics experience you also know that th e acceleration of all objects in free fall d ue to gravity is the sam e, ind epend ent of their m ass. You d ecid e to com pute how far the beam d eviates from a straight-line trajectory at d ifferent angles of inclinatio...
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This document was uploaded on 02/23/2014 for the course MANAGMENT 2201 at University of Michigan.

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