Station A: Force versus Current You will pass a current through a coil and measure the effect on the force exerted on a magnet hanging from a force sensor.. The experiment is setup with the magnet just below the top of the solenoid. This is to make alignment easier. Check to make sure that the magnet is still lined up. The Voltage Probe is connected to a 1 ohm resistor in order to measure current, the solenoid is connected to the DC side of the power supply. You should analyze and sketch the setup for your lab report. It should be wired on the side labeled 220 T(ums), check to make sure that the groups before you put the wires back to the original setup. Procedure: 1. 2. 3. 4. T49?\" 11. 12. 13. Analysis: Sketch the equipment and setup into your lab notebook, you will need this for your report. Start Logger Pro. You may have to setup the force probe manually. Zero the probes with the power supply turned off. You may have to do this on each individual input on the LabPro interface. Turn on the power supply. Press the collect \"button\" in Logger Pro. Slowly turn up the power supply, when you get up to 10 volts stop increasing, turn off the power supply immediately and stop data collection. To do this; keep an eye on the graph while turning the knob. Store the latest run on the experiment menu. Switch pole orientation by turning the magnet over and repeat. Change the wires to the other pair of coil terminals and repeat. To keep the field direction consistent move the wire from the red post to the other red post and from the black post to the other black post. Turn the magnet over and repeat. This should put the magnet back in its original configuration. At this point you should have 4 total trials, if you have extra time at this station you may repeat any trials that you wish. Return the wiring back to its original locations for the next group. Email the data to yourselves and let me know that you are ready to move on. You will need to do curve ts on segments of data, Excel does not do this very well, so work in Logger Pro. Create a graph of Force versus Current for each trial, curve t the data and compare. Are attraction and repulsion opposites of each other? This is not trivial, you need to compare values and trends. Do not just say, \"yes\\fStation B: Induced EMF versus Speed This exercise is constructed with a magnet hanging from a spring, the magnet is free to oscillate in a tightly wound coil. In order to make measurement of speed and frequency easier a string is passed through the end and attached to a mass hanger above a sonic detector. The oscillation of the magnet in the coil induces an EMF (potential difference) in the coil which is measured by a voltage probe. Procedure: 1. 2. 51'7" t\"'9.9C'.\"~'F" Analysis: 1. 2. 5" Sketch the setup for your lab report. Start the vibration by gently pulling down on the mass, get a feel for what the oscillation looks like and how long the experiment will run. You will need to work out how far you can pull the magnet and still get a clean run with minimal excess bounce and physical bumping. You may need to make minor adjustments of the equipment to ensure smooth movement. Start Logger Pro, the program should recognize both probes. By default there should be three time graphs, V, s, and v displayed. Set data collection to 5 seconds and 50 samples per second. Collect data and check the quality of the result. (Smooth, sensible, not measuring the distance to your lab partners hand, etc.) Store the latest run. Repeat the run and check for consistency. Turn the magnet over and do two more runs. Return the setup to the original configuration. Email the data to yourself and let me know you are finished. This section has a long analysis so you will probably not have time to nish it before you move on to the next station. To avoid clutter you should only have one run on the screen at a time, but you should have all three graphs. Insert two new graphs, set them up to show Potential vs Position and Potential vs Velocity respectively. What can you determine about the relationships of the quantities for the two graphs? (Hint: only 1 of them can or should have a curve t applied to it.) Compare the V vs t graph to the s vs t and v vs t graph. You need to look for relative values at specic points in time. For example what is the velocity (displacement) doing while V is at a maximum, minimum and zero. Curve t the V vs t, 2: vs t and v vs t graphs and compare the equations. Be sure to include only the freely oscillating portion of your graph, not the pre- release portion. Interpret all of your constants, as usual. How are the equations for the three graphs related? How are they different? Give special attention to the relative phases of the curves. Save frequently and be prepared to move on. \fPart C: Induction in a Second Solenoid In this part you will change the intensity of the eld in a solenoid by varying the current. The changing magnetic eld will induce an emf (potential) in the second coil. Sketch the setup for your lab report. Do not go over 10 volts when turning up the potential. Be sure to notice which probe channel is attached to each part of the solenoid. Procedure and Analysis: These two parts run together in this part. 1. Start Logger Pro, you will probably get a potential versus time graph. Add a second graph and have each represent a single potential versus time graph. Zero the probes. Turn on the power supply with the knob turned all the way down. Start collecting. Turn the dial on the power supply up fairly slowly, let it sit at a value for a period of time, then turn it back down fairly quickly. Autot both segments (rising and falling) on your graphs. Compare the two graphs visually, look at the relationships. Use the examine function and the slope function to compare numerically. Now that you have the window sizes set, take another run, this time raise and lower the setting several times at different speeds. 10. Is the highest peak related to the highest setting? If so, explain why this should be true, if not what is related to the highest induced peak. 11. Check your conclusion several times in the next run. 12. Describe the relationship between the sign of the induced emf and the power supply voltage. Save everything. 13. Change the wires to the AC side of the power supply. 14. Change the experimental set up to take 600 data points per second for a total of0.5 seconds. .U'PP'!\" 99074.0\" 15. Turn on the power supply and set the dial to around 15 on the arbitrary scale. 16. Collect data, this will only take 0.5 seconds. 17. The analysis for this graph should include curve tting your results. Compare the two graphs as above. Curve t the results. Compare the ts to each other in detail 18. Save your file and email it to yourself, let me know that you are finished with this part. 19. Step aside/move on. Part D: Tangent Galvanometer: The tangent galvanometer uses coils and a compass to measure current ow. What it \"really\" does is compare the magnetic eld at the center of the coil to the magnetic eld of the Earth. Since the Earth's magnetic field varies greatly, and in modern times is affected by noise from machinery, electricity and even from the metals used in modern construction methods (such as the structure that might be used to build a sturdy and long lived lab table.) Modern in this case means late 19th century. With the increased interest in electricity at that time, circuit based designs of meters became common and cheaper. The tangent galvanometer became a way of measuring magnetic fields instead. A quick web search will enable you to look at the craftsmanship that went into building tangent galvanometers in the early days. Currently the Hall Effect microchip allows for easy measurement of magnetic eld strength so that the tangent galvanometer is used mostly for teaching purposes and in instrumentation museums. The circuit will be set up as shown in the diagram. Make sure that those who have come before you have not changed the setup. Remember the DMM in should be SERIES with the rest of the circuit. Use the DMM to measure current. The ceramic resistor is there to act as ballast (limit current). Place the compass on the galvanometer and turn the setup so that the compass is Galvanm'm'" pointing parallel to the plane of the loops. 1. determine the appropriate range of currents to cause a variable and large deection of the compass needle. Be sure to include a description of how you arrived at the range. 2. Make a table of current versus angle of deection, reverse the direction of current ow and repeat. You will need at least seven points on each side of the center. Are the two directions symmetrical or related? 4. Plot the results on a graph; determine the mathematical relationship between current and deection. 5. Count the true number of turns. U.) Use the magnetic field strength equation for Wfor the coil (solenoid) and the following vector ideas to determine the magnetic eld of the Earth (plus noise) on your bench. By denition the direction of the Earth magnetic eld is the direction that a compass points. The force exerted by the eld is proportional to the strength of the eld, by the definition of force fields. ONI B Applied Bnet B Applied B Earth B Net B Earth B App. This enables you determine the value of the background magnetic field. This experiment should produce the background field, an angle versus current relationship, an angle versus field relationship, and a check against the force versus current relationship.\fPart De Galvanometer . Compass should be oriented 1 "area vector I(A Imax = 1A M. = 47 * 10 # Tim -70 " 70 B. ( I) - Bapp ( 8 ) But A Bapplied Solenoid N: # of loops/ turns O I Bearth Bapp tano : Bearth N # loops n = g meter to . ... . Bapp Bearth tan ( @) Bol = Mul EXPODelete v Ic BCH Merge & Center $ ~ % 9 Conditional Format Cell Formatting as Table Styles Format v Chart 1 X LL I S Z O angle current 70 2.5 1.38 0.19 PART D 0.97 16 loops 84.2105263 0.61 -30 0.42 0.12 O o 05 -0.12 -0.25 -0.4 0.65 -0.85 -1.28 -1.941