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Ferrite magnets Nd-Fe-B magnets. 1. Use the influence of magnets on iron filings to investigate the magnetic fields of the different magnets. Draw the magnetic fields lines on the diagrams, and indicate where the poles (strongest regions) of each of the magnets are.
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Ferrite magnets Nd-Fe-B magnets 1. Use the influence of magnets on iron filings to investigate the magnetic fields of the different magnets. Draw the magnetic fields lines on the diagrams, and indicate where the poles (strongest regions) of each of the magnets are. 2. How do the shapes and spacings of the filings depend on magnetic field strength and distance? 3. Evaluate the strength of each magnet quantitatively by determining the longest chain of paper clips that it can support. Write this number on or by the picture of each magnet. Make sure your chain extends in the direction of the strongest field, as determined in question 1, using a bent paper clip if necessary. Which magnet(s) exhibit the strongest fields?
4. Some currencies use magnetic ink. Are any bills in your wallet attracted to these strong magnets? If your answer is “Yes”, demonstrate your answer to one of the TA’s. 5. Do ferrofluids and iron filings arrange themselves in a similar manner when brought near a magnet? 6. What is the furthest distance you can hold the Nd-Fe-B cube magnet from the compass and reverse true N and S just by holding the magnet in place and spinning it? Make sure you have the magnet oriented in the direction of maximum effect. 7. Suggest an explanation for the formation of spikes (instead of a continuous particle distribution like the filings) in ferrofluids. • Consider the reaction for ferrofluid synthesis: 2 FeCl3 + FeCl2 + 8 NH3 + 4H2O --> Fe3O4 + 8 NH4Cl • Is this a redox reaction? If so, identify the species being reduced and oxidized. • What provides the driving force for this reaction to run?