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Unformatted text preview: Resistance and Ohm’s Law Report Class: Physics 182 Lab Summer I I TA: Joy Ding Date of Experiment: 7/19/10 Due Date: 7/21/10 Itzel Rodriguez Goal of Experiment: The purpose of this lab was to see how resistance and Ohm’s law works. The idea was to see how resistance affected an electrical current of an object. The other idea was to see how an ohmic device differs from a nonohmic device. I ntroduction, Theory, Derivation: One of the objectives of this lab was to use two different methods to finding the resistance of an ohmic device. Those two methods are by using Ohm’s law and by utilizing a digital multimeter. Ohm’s law could be obtained using resistance, voltage and current; the relationship between the three is V= IR. Resistance allows you to know how much voltage is needed to have a current flowing. When talking about fluid analogy, resistance lets you know how much pressure is needed for a body of water to go through a tube. In some cases resistance isn’t dependent on current. The current could change from high to low and the resistance would still be the same. When this happens it means that the object is ohmic. This can be tested by graphing voltage vs. current and if turns out to be a linear line that means the object is ohmic. To find the resistance of this object all you would have to do would be to find the slope of that graph. When looking at resistance in different kinds of circuits you will be able to see a difference. When two circuits have the same resistors but one is in series and the other is in parallel, there will be a difference in the total resistance obtained from the two. The resistance formula for a series is R s = R 1 + R 2 and the formula for a parallel circuit is = + 1Rp 1R1 1R2 . This means that a resistor in series would have more resistance than one on parallel. One way to find resistance is by using the formula = R ρlA where ρ is resistivity, l is length, and A is the cross sectional area....
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This note was uploaded on 09/13/2010 for the course PHYS 182 taught by Professor Greg during the Summer '08 term at Arizona.
 Summer '08
 greg
 Resistance, Work

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