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Unformatted text preview: potential difference? Make sure everyone gets a chance to manipulate the magnet and coil and
control the computer.
Can you discover any methods you didn't think of earlier? What is the largest potential
difference you can generate? CONCLUSION
How do your results compare with your predictions? Explain any differences, using
pictures or qualitative graphs where they are helpful. State clearly the physics involved.
List the important characteristics for inducing a potential difference in the coil of wire.
Explain how they are related to the magnitude and sign of the induced potential
difference. How do you get the largest potential difference? 172 PROBLEM #2: MAGNETIC FLUX
You are working on a project to build a more efficient generator. A web search reveals
that most existing generators use mechanical means such as steam, water, or airflow to
rotate coils of wire in a constant magnetic field. To design the generator, you need to
calculate how the potential difference generated depends on the orientation of the coil
with respect to the magnetic field. A colleague suggests you use the concept of
magnetic flux, which involves both the magnetic field strength and the orientations of
the coil and magnetic field. You decide that you need to calculate the magnetic flux
through the coil as a function of the angle between the coil and the magnetic field. To
help you qualitatively check your calculation, you use a computer simulation program.
You then quantitatively test your calculation by modeling the situation in the
Instructions: Before lab, read the laboratory in its entirety as well as the required reading in the
textbook. In your lab notebook, respond to the warm up questions and derive a specific prediction
for the outcome of the lab. During lab, compare your warm up responses and prediction in your
group. Then, work through the exploration, measurement, analysis, and conclusion sections in
sequence, keeping a record of your findings in your lab notebook. It is often useful to use Excel to
perform data analysis, rather than doing it by hand.
Read: Tipler & Mosca Chapter 28.1. EQUIPMENT
Diagram of Flux Simulation
screen to right.
Fr ame Read the sections The Magnetic
Field Sensor (Hall Probe) & The
Read the sections Flux Simulator
and Measuring Constant Magnetic
Field in the Software appendix. Magnet i c
Fi el d
Di r ect i on Fr ame' s
t hr ough
Fr ame Fr ame Ey e 173 Ey e' s v i ew of f l ux
passi ng t hr ough f r ame MAGNETIC FLUX – 1302Lab6Prob2
To make the measurement, a magnetic field sensor (Hall
probe) is placed midway between two Helmholtz coils as
shown to the right. The sensor can be rotated and the angle of
rotation measured. The sensor measures the amount of
magnetic field perpendicular to the area of the Hall effect chip
The MagnetLab application will be used to with a Hall probe. Sensor Helmholz
coils WARNING: You will be working with equipment that generates large electric currents.
Improper use can cause painful burns. To avoid danger, the power should be turned
OFF and you should WAIT at least one minute before any wires are disconnected
from or connected to the power supply.
If equipment is missing or broken, submit a problem report by sending an email to
firstname.lastname@example.org. Include the room number and brief description of the
problem. WARM UP
1. Draw the coil of wire at an angle to a magnetic field.
2. Draw and label a vector that you can use to keep track of the direction of the coil.
The most convenient vector is one perpendicular to the plane of the coil, the area
vector. Label the angle between the area vector and the magnetic field.
3. The magnetic flux for a constant magnetic field is the component of the magnetic
field perpendicular to the plane of the coil times the area of the coil. Write an
equation for the magnetic flux through the coil as a function of the strength of the
magnetic field and the angle between the area vector and the magnetic field
direction. For what angle is this expression a maximum? Minimum? PREDICTION
Calculate the magnetic flux through an area (the frame of the simulation or the Hall
effect transducer chip for the measurement) as a function of the angle that the area
makes with the direction of the magnetic field. Use this expression to graph the
magnetic flux versus angle.
In the simulation program, under what conditions will the “eye” “see” the most intense
blue color? The most intense red color? Will there ever be no color, or white? As the
174 MAGNETIC FLUX – 1302Lab6Prob2
Frame is slowly rotated, will the transitions in intensity be sudden, or gradual? Is the
change in intensity linear or something else? EXPLORATION
Open the Flux Simluator movie. Use the control bar with slider, which advances
through the movie, to control the rotation of the frame. Try it. Slider
As you rotate the frame, observe both the angle that the frame's area vector makes wit...
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This document was uploaded on 02/23/2014 for the course MANAGMENT 2201 at University of Michigan.
- Spring '14