HW #2 - Electric Fields

HW#2 Electric - MasteringPhysics Assignment Print View PSS 26.2 The Field Trip Learning Goal To practice Problem-Solving Strategy 26.2 for problems

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MasteringPhysics: Assignment Print View PSS 26.2: The Field Trip Learning Goal: To practice Problem-Solving Strategy 26.2 for problems involving the electric field due to continuous charge distributions. A straight wire of length has a positive charge distributed along its length. Find the magnitude of the electric field due to the wire at a point located a distance from one end of the wire along the line extending from the wire. MODEL: Model the distribution as a simple shape, such as a line of charge or a disk of charge. Assume the charge is uniformly distributed. VISUALIZE: For the pictorial representation: 1. Draw a picture and establish a coordinate system. 2. Identify the point P at which you want to calculate the electric field. 3. Divide the total charge into small pieces of charge using shapes for which you already know how to determine . This is often, but not always, a division into point charges. 4. Draw the electric field vector at P for one or two small pieces of charge. This will help you identify distances and angles that need to be calculated. 5. Look for symmetries in the charge distribution that simplify the field. You may conclude that some components of are zero. SOLVE: The mathematical representation is . Use superposition to form an algebraic expression for each of the three components of at point P. (Note that one or more components may be zero.) Let the coordinates of the point remain as variables. Replace the small charge with an equivalent expression involving a charge density and a coordinate, such as , that describes the shape of charge . This is the critical step in making the transition from a sum to an integral because you need a coordinate to serve as

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MasteringPhysics: Assignment Print View the integration variable. Express all angles and distances in terms of the coordinates. Let the sum become an integral. The integration will be over the coordinate variable that is related to . The integration limits for this variable will depend on your choice of coordinate system. Carry out the integration and simplify the result as much as possible. ASSESS: Check that your result is consistent with any limits for which you know what the field should be. Start by making simplifying assumptions appropriate for the situation. Part A The wire can be modeled as a line of charge if you assume which of the following? A. The diameter of the cross section is constant throughout the wire. B. The diameter of the cross section is much smaller than the length of the wire. C. The diameter of the cross section has the same order of magnitude as the length of the wire. D. The cross section has a circular shape. E. The cross section has a highly symmetrical, though not necessarily circular, shape. Enter the letters of all the correct answers in alphabetical order. Do not use commas. For instance,
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This note was uploaded on 09/22/2009 for the course PEP 112 taught by Professor Whittaker during the Spring '07 term at Stevens.

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HW#2 Electric - MasteringPhysics Assignment Print View PSS 26.2 The Field Trip Learning Goal To practice Problem-Solving Strategy 26.2 for problems

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