Ch21_SolomonE

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= Lab: What is the relationship between magnetic field strength and distance from the source? =

Pre-lab Assignment Magnetic field strength will inevitably decrease as the distance from the source of it increases. Magnetic fields seem to have fairly similar properties to electric fields from what we have learned thus far. In an electric field, an increase in distance will decrease the field strength. Using the assumption of these two fields having parallel properties, the magnetic field strength will decrease as distance increases. We can measure distance from the source of magnetic field using a meter stick or something. Also, we can measure magnetic field using a magnetic field sensor.
 * 1) The objective is stated in the title. What is your hypothesis? (Attempt to answer the question, to the best of your knowledge.)
 * 1) What is the rationale for your hypothesis? (Provide detailed reasoning here. This may take the form of a list of what you already know about the topics, with a summary at the end.)
 * 1) How do you think you might test this hypothesis? (What might you measure and how?)
 * 1) Read the entire procedure through.
 * 2) Design __data table(s)__ in order to record your observations __and__ calculations. Do this in Excel a post this draft on your wiki.

Data Table:


 * Distance (m) || Magnetic Field (T) ||

=Making a Motor Activity=

Hypothesis: A simple motor can be made using wire, magnets and a battery b/c of the torque on a circular/square circuit.

Materials: Wire Magnets Battery Paper clips

Procedure: Wrap the wire into a circle. Make sure that 7 cm is hanging out on opposite sides of the circularly wrapped wire. Sand both sides of one side of the wire. Sand 180 degrees on the other side of the wire. Place the paper clips on either side of the wire. Stick the magnets on top of the battery. Place the paper clips in a hooked manner on top of the magnets and battery.

Data: How do I put a video on?

media type="file" key="this be a project argh.mov" width="300" height="300"

A galvanometer detects and measures electrical currents. A coil is set up attached to a magnet, which is then set up in a current. As the current passes through the device, a needle deflects proportional to the torque provided by the set-up. It is opposed by a spring, so greater deflection requires greater torque. A motor converts energy into mechanical motion. A generator does the reverse of this process. The motor takes the electrical energy provided from the battery/coil combination. It then uses magnetic fields to spin the coil. This motion from the coil creates mechanical energy. If both of the rotors had all of their insulation sanded off, then when the coil flipped, it would immediately reverse its direction of torque, due to a reverse in the direction of magnetic force. If only half of the arm is sanded off, then inertia will carry the rotor back to the position where magnetic force pulls it in the same direction. We would have to take this process and reverse it. Instead of having the wire power something using the electrical to kinetic force, we would have to have some mechanical force turn the wire. We would have to remove the battery and place some sort of turning mechanism in its place. This would make the electrical energy the product and the kinetic energy the catalyst.
 * Discussion Questions**
 * 1) How does a galvanometer work?
 * 1) Define motor and generator.
 * 1) A motor is a device which converts electrical energy into mechanical energy (motion). Explain how your motor does so.
 * 1) Why does the one rotor support have only ½ of its insulation sanded off?
 * 1) How could the motor you built in be converted to a generator? Describe carefully what would have to be changed and what the result would be.

Conclusion: During this lab, we learned about the workings of a simple motor. We have learned that a the current in collaboration with the magnetic field have produced a magnetic force able to turn the coil. This has also proven the hypothesis that torque makes the wire turn. This has also proven to be a practical usage of magnetic force. Motors are used everywhere, and they utilize the exact same principle that we have applied during the lab. These motors, though, have many more coils (causing more torque), are more tightly wound, and also are more stable. The materials that we used and the methods that we used them produced a very rough circuit prone to falling off of the hook apparatus and falling out of favor with the magnetic field.

= Lab: Magnetic Force on a Wire =

Answers to these questions are to be written in your **group wiki** //BEFORE// coming to class on lab day. > The relationship between magnetic force and magnetic field strength, length of wire, and angle between the field and the conductor will be a direct relationship. This is shown by F=BILsin(theta). F is magnetic force, B is magnetic field strength, L is length of wire, and theta is angle between field and conductor. This can be tested by changing the field strength, current, and length, and theta, all one at a time.
 * Pre-laboratory Questions: **
 * 1) The objective is stated as a question. What is your hypothesis? (Attempt to answer the question, to the best of your knowledge.)
 * 1) Include the rationale for your hypothesis (Provide detailed reasoning here. This may take the form of a list of what you already know about the topics, with a summary at the end.) My rationale is the knowledge of the equation shown above. Also, I have learned that if a constructive component of a force increases, the magnitude of the force will increase as well.
 * 2) How do you think you might test this hypothesis? (What might you measure and how?)

It is the z-component when paired with the other two components forming an x/y plane
 * 1) Read the entire procedure through.
 * 2) Design __data table(s)__ in order to record your observations __and__ calculations. Do this in Excel (preferable), and post a copy on your wiki.
 * Theoretical Force (N) || Experimental Force (N) || Magnetic Field (T) || Current (A) || Length of Wire (m) || Angle Between Field and Current (degrees) || Percent Error (%) ||
 * 1) Answer the following questions:
 * 2) How is the direction of the magnetic force oriented with respect to the directions of magnetic field and current which produced it?
 * 1) Answer the following questions:
 * 2) How is the direction of the magnetic force oriented with respect to the directions of magnetic field and current which produced it?
 * 1) Answer the following questions:
 * 2) How is the direction of the magnetic force oriented with respect to the directions of magnetic field and current which produced it?

The closer the angle is to 90 degrees, the higher the force will be assuming that current and magnetic field are constant. 90 degrees.
 * 1) How do changes in the angle between the current and the magnetic field affect the force acting between them?
 * 1) What angle between the current and the magnetic field produces the greatest force?

180 degrees or 0 degrees.
 * 1) What angle between the current and the magnetic field produces the least force?

The longer the length of wire, the greater the force. This is a direct relationship.
 * 1) How is the magnitude of the force of magnetism related to the magnitude of the length of the wire carrying the current?

.00559=BLsin90 .00559=B(.042)sin90 B=.13T F=BILsin90 F=.13(.352)(.042)sin90 F=.00197N
 * 1) A graph of force vs. current has a trendline with an equation of y = 0.00559x. What is the theoretical magnetic field strength of the magnet used in this experiment if the loop is 4.2-cm long? Show your work.
 * 1) Find the magnetic force on the conducting loop described above, when the current is 0.352-A.