Exercises for Thursday, October 23
[1] There are a few different resistors in an envelope in your kit. Some of them are marked Yellow Violet Gold Gold, while others are marked Red Red Gold Gold. Determine, using any method that you wish, which type of resistor has the greater resistance.
[2] After you have finished Part [1], each group member should come up to the desk and grab a multimeter. This meter will be yours to keep, so be careful with it. You will need to use it for several experiments over the next few weeks, so be sure to bring it to class with you. For today's experiments, we will be using the multimeter as an Ammeter, a device that measures electrical current.
[3] Do Experiment 5.1 on p. 420 of your text. For the positive connection to the Ammeter, use the hole marked 10ADC. For the negative connection, use the hole marked COM. The dial should be set to 10A. If you want to be safe, make sure that your ammeter is disconnected from your circuit whenever you are changing its dial. If you have any questions about using the ammeter for the first time, chat with John to make sure you know how to use it. You have to be careful with ammeters!
[4] Set up the circuit below involving your battery pack, one ammeter, and the decade resistance box. Before you hook anything up, set the decade resistance box to read
0 5 0.
The number shown by the dials of the decade box represents its resistance in Ohms. Red digits are tenths of Ohms. While the box is hooked up in your circuit, make sure that it never gets set below 1 Ohm. How does the current flowing through the ammeter change as you change the resistance of the decade box? Do high resistances give you large currents or small currents?
[5] Now hook up the circuit depicted below. The zig-zag symbol represents one of the resistors in your box that is marked with a Brown Black Black Gold color code.
What is the resistance of your Brown Black Black Gold resistor?
[6] Now replace the resistor in your circuit from Part [5] above with a light bulb. Use this new circuit to determine the resistance of your light bulb.
[7] Finally, replace the light bulb by two Brown Black Black Gold resistors in series, so that your total circuit looks like:
| Use this circuit to determine the total resistance of your two resistors |