Ohm\'s law lab questions: Remember, from Ohm\'s law V = I*R, and the slope from
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Question
Ohm's law lab questions:
Remember, from Ohm's law V = I*R, and the slope from the 1 vs V graph should he 1/R. Present your findings in a detailed lab report and answer the following questions in the discussion section of the report: What does the constant slope in the 1 vs V graph mean? Is having a resistor in a circuit a good thing or a bad thing? Defend your answer. Why is an ammeter placed in series with a resistor to measure the current through the resistor? When measuring the voltage across a resistor why is the voltmeter placed in parallel?Explanation / Answer
1- The graph IvsV represents how the resistance varies as more current and voltage is applied. If the electric field is independent the resistance is independet from the voltage and the resistor follow the Ohm Law. That means that the graph Ivs V will represent a line.
2- yes it is good, all the machines that consume electricity are resistance but it is not good to have resistance in the cable because you will loose part of the current you want to transmit
3- the ammeter is placed in series to meassure the current that pass through the resistance in the circuit. ( the local current)
4- The voltage (misnamed voltage) is defined as the difference in electrical potential between two points of a circuit. That is why the voltmeter is connected in parallel, because it has to be between these two points. A slightly different definition is that the voltmeter measures the force with which the current flows.
Unlike the ammeter, which is connected in series for current to flow through it and so can be measured.
As additional data, it is good to know that the internal resistance of the voltmeter should be very high. This by connecting in parallel a current divider is created, and if the internal resistance of the voltmeter was low, some part of the current is diverted through this, so the circuit conditions change and measurement would not be correct.
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