course Phy 202 ??????????????assignment #004004.
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16:01:59 Query introductory set #1, 10-17 Explain how to find the potential difference in volts between two given points on the x axis, due to a given charge at the origin.
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RESPONSE --> You divide the J of work to move between the two points by the charge at the given point. Potential difference = 28.8 J/ -2.083 C = -13.83 J/C or -13.83 V confidence assessment: 3
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16:05:52 ** Potential difference is the work per Coulomb of charge moved between the two points. To find this work you can multiply the average force on a Coulomb of charge by the displacement from the first point to the second. You can find an approximate average force by finding the force on a 1 Coulomb test charge at the two points and averaging the two forces. Multiplying this ave force by the displacement gives an approximate potential difference. Since the force is not a linear function of distance from the given charge, if the ratio of the two distances from the test charge is not small the approximation won't be particularly good. The approximation can be improved to any desired level of accuracy by partitioning the displacement between charges into smaller intervals of displacement and calculating the work done over each. The total work required is found by adding up the contributions from all the subintervals. University Physics students should understand how this process yields the exact w ""ork, which is the integral of the force function F(x) = k Q / x^2 between the two x values, yielding total work W = k * Q * 1 Coulomb ( 1 / x1 - 1 / x2) and potential difference V = k * Q ( 1 / x1 - 1 / x2). **
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RESPONSE --> I did not understand correctly what the question was asking for though I found the potential difference I did this using the joules of work. I should have noted that this may not be given and you may need to calculate it yourself. So you would find the average force by averaging the two forces found with test charges. Then you would multiply the ave foce by the displacement. self critique assessment: 2
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16:16:34 Explain how to find the potential difference between two points given the magnitude and direction of the uniform electric field between those points.
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RESPONSE --> If you know the magnitude and direction it is simply force multiplied by displacement. confidence assessment: 1
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16:17:19 ** The work per Coulomb done between the two points is equal to the product of the electric field E and the displacement `dr. Thus for constant field E we have V = E * `dr. **
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RESPONSE --> Ok.. I didn't use the right notation, but I understand the process. self critique assessment: 2
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16:20:04 Explain how to find the average electric field between two points given a specific charge and the work done on the charge by the electric field as the charge moves between the points.
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RESPONSE --> First you find the force from the work done by dividing the J of work by the distance between the two points. This gives you the Newtons of force. You then take the N and divide it by the charge to find N/C which is how electric fields are measured. confidence assessment: 2
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16:20:32 ** You get ave force from work and distance: F_ave = `dW / `ds. You get ave electric field from work and charge: E_ave = F / q. An alternative: Find potential difference `dV = `dW / q. Ave electric field is Eave = `dV / `ds **
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RESPONSE --> ok self critique assessment: 3
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16:24:52 In your own words explain the meaning of voltage.
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RESPONSE --> voltage is the electric potential difference per charge. It depends on a electric field and is aquires energy. confidence assessment: 1
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16:26:20 ** Voltage is the work done per unit of charge in moving charge from one point to another. **
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RESPONSE --> My definition was over complicated. It is more simply said that it is the work per unit charge when the charge is moving from point A to point B. self critique assessment: 2
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