Rank in order of brightness the bulbs a b c d and e

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Unformatted text preview: t is missing or broken, submit a problem report by sending an email to [email protected] Include the room number and brief description of the problem. 81 SIMPLE CIRCUITS – 1302Lab4Prob1 PREDICTION Restate the problem. Rank, in order of brightness, the bulbs A, B, C, D, and E from the brightest to the dimmest (use the symbol „=‟ for "same brightness as" and the symbol „ >‟ for "brighter than"). Write down your reasoning. EXPLORATION Reference Circuit I Connect Circuit I to use as a reference. Observe the brightness of bulb A. Replace the bulb with another one and again observe the brightness. Repeat until you have determined the brightness of all your bulbs when they are connected into the same type of circuit. If the bulbs are identical, they should have the same brightness. Note: Pay attention to large differences you may observe, rather than minor differences that may occur if two "identical" bulbs are, in fact, not quite identical. How can you test whether minor differences are due to manufacturing irregularities? Circuit II Connect Circuit II. Compare the brightness of bulbs B and C. What can you conclude from this observation about the amount of current through each bulb? Is current "used up" in the first bulb, or is the current the same through both bulbs? Try switching bulbs B and C. Based on your observation, what can you infer about the current at points 1, 2, and 3? How does the brightness of bulb A (Circuit I) compare to the brightness of bulbs B and C (Circuit II)? What can you infer about the current at point 1 in each of the two circuits? Circuit III Connect Circuit III. Compare the brightness of bulbs D and E. What can you conclude from this observation about the amount of current through each bulb? Describe the flow of current around the entire circuit. What do your observations suggest about the way the current through the battery divides and recombines at junctions where the circuit splits into two branches? How does the current at point 1 compare with the currents at points 2 and 3? 82 SIMPLE CIRCUITS – 1302Lab4Prob1 How does the brightness of bulb A (Circuit I) compare to the brightness of bulbs D and E (Circuit III)? What can you infer about the current at point 1 in each of the two circuits? Comparing the three circuits, does the amount of current at point 1 appear to remain constant or to depend on the number of bulbs and how they are connected? CONCLUSION Rank the actual brightness of the bulbs. How did this compare to your prediction? Make sure you adequately describe what you mean in your comparisons, i.e. “the same brightness as”, “brighter than”, “dimmer than”. What type of circuit is used in your track lighting? Circuit II is called a series circuit and Circuit III is called a parallel circuit. Can you use conservation of energy and conservation of current to explain your results? The rate that energy is output from a bulb is equal to the potential difference (voltage) across the bulb times the current through the bulb. Does a battery supply a constant current or a constant potential difference to circuits? To check your understanding, rank the brightness of the bulbs in the following circuits. Use the lab equipment to see if your answer is correct. 83 SIMPLE CIRCUITS – 1302Lab4Prob1 84 PROBLEM #2: MORE COMPLEX CIRCUITS It is the holiday season once again so you have decided to put up your decorations. You have three strings of decorative lights and only one electrical outlet between the tree and your doorway. To have enough lights to cover the tree, you will need to connect two of your light strings together end to end. The other set of lights will be enough to light up your doorway. You know that you have a few ways of connecting the lights. You want to hook up the lights so they are all as bright as possible. In order to determine which arrangement gives the most light before making your final decorating plans, you build a reference circuit and a model of the possible ways of connecting the sets of lights. In your model one light bulb represents a light string. Instructions: Before lab, read the laboratory in its entirety as well as the required reading in the textbook. In your lab notebook, respond to the warm up questions and derive a specific prediction for the outcome of the lab. During lab, compare your warm up responses and prediction in your group. Then, work through the exploration, measurement, analysis, and conclusion sections in sequence, keeping a record of your findings in your lab notebook. It is often useful to use Excel to perform data analysis, rather than doing it by hand. EQUIPMENT You will build four simple circuits shown below out of wires, bulbs, and batteries. Legend: light bulb battery Use the accompanying legend to build the circuits. wire Note: Check to make sure the light bulbs are all of the same type. To find identical bulbs look for markings on the base and check to see that the color of the...
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This document was uploaded on 02/23/2014 for the course MANAGMENT 2201 at University of Michigan.

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