Lab Summary 1 - Lab report covering the \"Equipotential Lines\" lab. PDF

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Lab report covering the "Equipotential Lines" lab....

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PHYS 216

1 February 2018

Equipotential Lines

Kristen Holmes Table 5

Dakota West Avery Walton 25 January 2018

Holmes 1

PHYS 216

1 February 2018

Holmes 2

PURPOSE: The purpose of this experiment was to use a voltmeter to locate equipotential lines between pairs of differently shaped conducting regions. Using the equipotential lines that were found, the electric field lines can be determined. THEORY: All charged objects have an electric field that radiates from the object. However, electric fields are never measured directly. Instead, another property, called the electric potential difference (voltage), is measured. For this procedure, the voltage was measured between one positive charge and one negative charge. Measuring the voltage between two charges is how to find equipotential lines, which are lines where the voltage remains the same. Equipotential lines then provide the path of the electric field lines since they are perpendicular to one another. Using the distance between each equipotential line and the positively charged plate, the value of the electric field can be determined by dividing the voltage by the distance (E=V/d). To perform an error analysis on these values, the standard deviation of the mean can be found for each of the equipotential lines. Standard Deviation of The Mean :

Electric Field:

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PROCEDURE: To set up this procedure, the first thing that was done was setting up the conductors. To do this, a conducting sheet was placed on a corkboard. Then, two push pins were placed in the center of the conducting regions, one in each. To connect the power supply to the conductors, banana cables with alligator clamps on one end were used. The first cable was plugged into the positive input on the power supply. The alligator clamp on the other end of the cable was then connected to the push pin in the center of the positive conducting region. The second cable was then connected to the negative input on the power supply. Similarly to the first cable, the other end was connected to the remaining push pin in the negative conducting region. After the conductors were connected to the power supply, the voltmeter was connected to the conductors. A new cable was connected to the second cable's extension near the push pin, and the other end was plugged into the negative input of the voltmeter. The last cable was plugged into the positive input of the voltmeter, and the other end was used as a detector. Once the set up was complete, each person used a piece of graphing paper and replicated the shape of each conducting region and its proper location. To start the procedure, the power supply was turned on, and the voltage was set to 5V. Using the detector, the first person in the group started to locate points between the conducting regions. Five points were located; all of which had the same voltage. These points created the first of three equipotential lines. The next five points, which had a different voltage than the first five points, were located by the second person in the group. This created the second equipotential line. Lastly, the final five points were located by the third person to create the last equipotential line.

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After each point was located, all three students would mark the location of the point on their graph paper that contains the proper conducting shapes. Then, each student would connect each set of points containing the same voltage to produce the three equipotential lines. Once the equipotential lines were drawn, the electric field lines were drawn using the knowledge that equipotential lines and electric field lines are perpendicular to one another. Each student ended with a sheet of graph paper containing the proper shapes of the conducting regions, three sets of five points containing the same voltage, three equipotential lines connecting those points, and electric field lines perpendicular to the equipotential lines. All of the previous actions were then repeated using two more arrangements of conducting shapes that are different from the first, and different from one another. Therefore, each student should conclude this procedure with three sheets of graph paper, each containing a different arrangement of shapes for the conducting region. Each sheet of graph paper should have fifteen points, three equipotential lines, and the proper electric field lines connecting the two shapes for the conducting region. For this procedure a set of calculations were made. These calculations were done for all three arrangements of shapes. First, the average voltage was found for each equipotential line within a conducting region. These averages were used to calculate the standard deviation for the voltage of each equipotential line. The next calculation required some measurement. Using a ruler, the distance between each equipotential line and the positive conducting region, was measured. This provided the three measurements of d1,d2, and d3 for each set of conducting regions. The first equipotential line would correlate with d1, the second with d2, and the third with d3. To calculate the electric field at each equipotential line the formula E=V/d was used, "V" meaning voltage, and "d" being substituted by the previous measurements of d1,d2, and d3,

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corresponding to their appropriate equipotential line. The results should consist of nine standard deviation solutions and nine electric field values. In this experiment, I was responsible for locating five points of the same voltage for each set of conducting regions. As well as performing my own calculations.

This is the apparatus used in the procedure. https://www.amazon.in/Aplab-LQ6324T-Output-Variable-Regulated/dp/B00VUMTMN8 https://ftaelectronics.com/handheld-digital-multi-tester-ammeter-voltmeter-resistancemultimeter.html

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1 February 2018

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DATA: See attached diagrams. ANALYSIS: See attached work. CONCLUSION: This experiment proved to produce fairly accurate results with little error. Only one equipotential line that was located during this experiment had a deviation greater .1V. All other equipotential lines, excluding one other with a deviation of .055V, had deviations below .028V. These low values conclude that there was little error in the equipment and little error in the execution of the procedure. The small deviation that can be seen, including the two greater than .05V, could have possibly been caused by slightly inaccurate placement of the detector or even an uneven level of pressure applied to find each point. This change in pressure could lead to an inaccurate, or slightly off, reading of the points voltage on the voltmeter. The results of the electric field calculations cannot be compared to a theoretical value to prove their accuracy. However, their values can be justified as correct or incorrect based on knowledge of an electric field. The value of an electric field should decrease as it gets farther away from the positive charge it radiates from. In this procedure, since a positive and negative conductor are used, the electric field values should follow the same decreasing pattern as they approach the negative conductor. The values calculated in this procedure do indeed follow this pattern. For example, in Diagram 1 and Diagram 3, the electric field produced by the equipotential line closest to the positive conductor had a value of 5V/cm. The equipotential line in the center of the conducting region had an electric field with a value of 1.67V/cm. The value of the electric field produced by the equipotential line farthest away from the positive conductor

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was 1.25V/cm. Therefore, based on the results of both calculations that were made, it can be determined that overall this experiment produces accurate results with little error....