| Physical Science - FME [Phys 101] Spring 2004 |
[1] Check out the circuit below.
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Are any bulbs in series? If so, list them. |
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Are any bulbs in parallel? If so, list them. |
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Predict the relative brightnesses of Bulbs A-E. After you have done so, set up the circuit and check your predictions. |
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(d) Predict what will happen to the brightness of Bulbs A and B when one of the C/D/E bulbs is unscrewed. Check your prediction. |
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(e) What happens to the other two C/D/E bulbs when one of them is unscrewed? Explain. |
[2] You have a board of five mounted coils of wire in your kit. The five pieces of wire are labeled (1) 10 meters of 22 gauge Copper wire, (2) 10 meters of 28 gauge Copper wire, (3) 20 meters of 22 gauge Copper wire, (4) 20 meters of 28 gauge Copper wire, and (5) 10 meters of 22 gauge Copper-Nickel wire. For the experiment below, use only the first four {copper} coils.
By using the circuit below and varying which of the first four coils of wire you use in your circuit, rank your four coils from lowest resistance to highest resistance.
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What do your results imply about the effect of the length of a piece of wire on its resistance?
What do they imply about the effect of the gauge of a piece of wire on its resistance?
[3] As a group, complete the exercises below. All of the squares are identical.
{1} Which of the circuit diagrams below can be used to represent the same physical circuits; that is, which circuits have the same electrical connections?
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{2} Two students are predicting the brightness of identical bulbs in the circuit below.
Student 1: "All the current is through A. Then it divides between B and C so they will be equally dim, lots dimmer than A. Then the current comes together again and it all goes through D. Bulb D will be the same brightness as Bulb A."
Student 2: "I think D will be a lot dimmer than A; in fact, maybe it won't light at all. There won't be much current left after it passes through A and B and C. Maybe D will be bright and A will be dim; it depends on the direction of the flow through the circuit. This would be a good test to find the direction of the current."
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Do you agree with Student 1, Student 2, or neither? Explain your reasoning.