Q1. i. [0.75 pts] Imagine that in Step E8 of the lab manual, the compass is placed due East of the wire, and the current is going upward. Draw a vector diagram for the magnetic field(s) felt by this compass with the current in the wire OFF. The diagram should show vector(s) representing individual magnetic fields from any relevant sources, as well as a vector that magnetic field vectors clearly. represents the total magnetic field at that location. Label the cardinal directions (N,S,E,W), and ii. [0.75 pts] Repeat part (i) but for the case with the current in the wire ON. ili. [0.5 pts] In the above scenario, how would the compass respond when you turn on the current? Explain your answer. E2. Test your setup: turn the power supply on and verify that you get a current of about 2.0 A. (This may not correspond to 2.5 V, which is ok) Do not leave the supply on for more than 10 seconds to avoid overheating. Note the current and the number of wires in your setup. 0 = North E3. Using a compass observe and record the direction of the magnetic field at several points near the wire when the current is zero. Does this agree with the measurements you made in experiment C? E4. Place the compass somewhere on the box's platform, BEFORE you turn on the power supply, predict what you expect to see when the current is not zero. Use the figure on the right to help, and consider the right hand rule for generating magnetic fields from a straight current. Which way does the thumb point? Which way do the fingers point? E5. Now turn on the power supply, and which way the compass points with the current on. What does this have to do with the magnetic field where the compass is? Start with the compass north of the wires. Now move the compass to directly north of the wires. Which way does the field point there? Also note the field direction with the compass E, S, and W of the wires. E6. Is the direction and shape of the magnetic field you observe consistent with predictions made with the right hand rule? E7. Change the direction of the current through the straight wire. Is the magnetic field consistent with the right hand rule? E8. At what position relative to the wires is the magnetic field of the current perpendicular to the Earth's magnetic field (Choose N,S E, WY? Set the compass at this position. Are there any other places that you could place the compass so that the magnetic field produced by the current is perpendicular to Earth's field? Check with your TA to make sure you placed the compass at the right spot. West / E Nors Field compass relative E9. Record the angle the needle makes on the compass. Turn the power supply back on, letting the needle settle, and record the angle it makes with the current on. Does it point in the direction the right hand rule would suggest for it to? Why or why not? Adjust the current until you get to a 45 degree angle
