Answer Happy

9.1.1 The magnetic field surrounding a current-carrying wire. 1. The rheostat will be used in this experiment to limit the current and protect the equipment. At times the resistance will need to be decreased in order to observe an effect. Start by examining the rheostat. Figure out how it functions as a variable resistor. How should it be wired? Which way will you move the slide to increase the resistance? Make a sketch illustrating its use.
2. Take two power leads (with large #14 fork terminals) and connect to the positive and negative terminals of the DC power supply. See Fig. 9.3. Use two other connecting leads and complete a series electric circuit (one big loop) that includes the rheostat, the tapping switch, and the ammeter. 3. In 1820 the Danish physicist Hans Oersted was teaching a class and demonstrating an electric circuit using a Voltaic-pile battery. There was a compass on the demonstration table near the circuit wire, and Oersted noticed that the compass needle was deflected when the wire was brought close to it. 4. Start with the rheostat slide in the middle position. Place the compass under one of the connecting wires, such that the compass needle is parallel to the wire. Close the tapping switch momentarily and observe the compass needle. If you don't see a deflection, reduce the resistance of the rheostat and try again. Note whether the compass needle swings clockwise or counterclockwise. Observe the direction of deflection. Sketch the results.