Only the best is good enough

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1 Class: Lecture Instructor: Lab Instructor: University Physics II Dr. Bin Zhang Dr. Michael Zelin Dates: Lab performed 10/27/2016 Report submitted 11/03/2016 Only the best is good enough Ole Kirk Christansen, founder of UNIVERSITY PHYSICS II Lab 7: FARADAY S LAW Laboratory Report by Group 12 Ryan Steven Brumwell (RB) Darryl Dromgoole II (DD) Patrick Cale Quinn (PCQ) Content Page Assessment points: base max novelty max 1. Objective 2 2. Introduction 2 _ 10 _ Apparatus & Materials 2 _ 20 _ Procedure & Results 4 _ 40 _ Analysis & Summary 6 _ 10 _ Questions 8 _ 5 _ References 8 _ 10 _ Acknowledgments 9. Credits 10. Appendices 10 _ 5 _ 10

2 Arkansas State University Chemistry & Physics Department 1. Objective: In this lab, the group will be looking into Faraday s Law of Induction, the group will also investigate how magnetic flux is present in inductors. The group will also learn about Len s Law and its effect on magnetic flux. 2. Introduction: According to Faraday s Law of Induction the electromotive fore equals the turns in the wire times the rate of change of the magnetic flux. The relationship can be viewed in Equation 1. Equation 1 ε = N ΔΦB Δt The direction of current is found by using the right-hand rule, and the magnetic flux is positive from the north pole of a magnet. The group will bring a magnet close to an inductor and examine the change it has on the voltage. The change in voltage will be due to the magnetic field and its relationship to voltage. Once again this relationship can be seen in Equation Apparatus and Materials: This lab many different pieces of equipment, the group will use 2 Inductors, the LabQuest Mini to collect data, a voltage probe, a power amplifier with an audio cable to allow for AC current, alligator clips to connect all the wires, and a bar and horseshoe magnet. Figure 1 is a picture of all the equipment used during this lab. Figure 1 Apparatus 4. Procedure and Results: Part I The Vernier LabQuest Mini was plugged into the USB port in the computer, and the voltage probe was connected to the Mini through Channel 1. The black alligator clip of the voltage probe was used to connect the black wire of the inductor. Likewise, the red alligator clip of the voltage probe was connected to the white wire of the inductor. Once this was complete, Logger Pro was opened and the duration set to 2 seconds with the sampling rate set to 500 samples/second. The probe was then Zeroed before proceeding to reduce any errors in false readings through the probe. Under this set up data was then collected. At this point one end of the horseshoe magnet was brought to the inductor (without the iron bar inside the inductor) and then pulled away quickly. The resulting graph was auto scaled and is shown as Figure 2.

3 Figure 2 Voltage through the Inductor due to a Magnet Next the iron bar was inserted into the inductor and the above steps were repeated. Figure 3 is the resulting graph. Figure 3 Voltage through the Inductor due to a Magnet and Iron Bar

4 Part II The same data collection setup as in Part I was used for the next portion of this lab. The iron bar remained in the inductor and the horseshoe magnet brought flush against the inductor. Data was then collected, and the magnet quickly pulled away from the inductor after waiting a single second of time. The data received through these steps is shown in Figure 4. Figure 4 Voltage through the Inductor with Magnet Removal, with Iron Bar Again, the above procedure was repeated, this time with the iron bar removed from the inductor. Figure 5 shows the resulting voltage. Figure 5 Voltage through Inductor with Magnet Removal, without Iron Bar

5 Part III To increase the investigation of voltage and magnetism voltage was added to the inductor through a power amplifier. The power amplifier was hooked up and flipped on. The power amplifier program was opened, started, then stopped, and closed. The program was then reopened, since it doesn t correctly open the first time, and the frequency set to 1000 Hz. An alligator clip was connected to the black wire on the second inductor, and that was connected to the black port on the power amplifier. A second alligator clip was connected to the white wire on the inductor, and that was connected that to the red port on the power amplifier. Finally, the current monitor was plugged into the back of the amplifier into the LabQuest Mini. With the connections established, the data collection settings were changed to (the clock icon beside the collect button) to have a duration of 0.01 seconds and 10,000 samples per second. The two inductors were set side by side, on their ends, so that they are touching and the data collection was made. This collection is shown in Figure 6. Figure 6 Voltage of the Inductors and Power Amplifier The same set up was used for the next two data collections however, the inductors were moved a half inch apart for each new collection. Figure 7 shows the collection at a half inch separation and Figure 8 at one inch separation. The current through the inductors is also shown in Figure 9. Figure 7 Voltage of Inductors at ½ Inch

6 Figure 8 Voltage of Inductors at 1 Inch Figure 10 Current Through the Inductors 5. Analysis & Summary Part 1 6.) Given that your emf voltage either started with a maximum (positive) or minimum (negative) peak, what can you induce about the magnetic pole you used in step 4? Is the pole you used north or south? Our first major peak was in the negative quadrant of the graph this tells us that we used the south pole of the magnet. 8.) What does this tell you about including the iron bar? When the iron bar was inserted into the inductor the graph in figure 3 deviated less than the graph in figure 2. There were less peaks in the graph as well. 9.) Which direction is the inductor wound? Include a sketch of the inductor and the direction of the wire. Since our voltage is in the negative direction the inductor is wound clockwise, giving us a negative voltage and current. But in my opinion since we are using alternating current AC the direction shouldn t matter because the current is changing direction anyways. The only change would be in the direction of the magnetic field. Part II 12.) Repeat step 11, except without the iron bar in the inductor. What does this tell you about the magnetic field and iron bar? Figure 5 When the iron bar was removed from the inductor the voltage on the graph became more stable compared to when the iron bar was in the inductor, see figure 4 and 5. On figure 4 there was a major spike in the negative direction when the magnet was taken away from the inductor. The deviation from the mean voltage was less when no bar was in the inductor.

7 Part III 18.) What do the results tell you about the relationship between distance and the magnetic fields? The greater the distance the weaker the magnetic field was, and since the magnetic field was weaker it had less of an effect on the voltage. Comparing figure 6 and 7 you can clearly see there is less fluctuation in the voltage. There were still a few peaks in both graphs but in figure 7 the data is closer together. 7. References 1. Electrostatics: Charging Objects by Friction, Lab Manual, University of Virginia,

8 10. Appendix: Supplemental Materials IMG_3488.MOV

University Physics II Dr. Michael Zelin Thursday 2:00pm 3:50pm. Faraday s Law. Group 9 Braden Reed Shawn Newton Sean-Michael Stubbs

University Physics II Dr. Michael Zelin Thursday 2:00pm 3:50pm Faraday s Law by Group 9 Braden Reed Shawn Newton Sean-Michael Stubbs Lab Performed October 27, 2016 Report Submitted November 3, 2016 Objective: