LINK TO SIMULATION IS HERE: https://phet.colorado.edu/sims/html/charges-and-fields/latest/charges-and-fields_en.html

PART 1:

Part | - The Electric Field of a Point Charge Start the simulation "Charges and Fields" (if you haven't done so already) by clicking on the image below. Charges And Fields We are going to take numerical data in this activity, so we need some references points (a coordinate system) and some measuring tools. Select the check box for "Voltage" Select the check box for "Values." Select the check box for "Grid." Drag and drop a single positive +1 nC charge in the center of the grid. Place a yellow E-Field sensor in several locations near, but not on top of, the point charge. Use this sensor to check three properties of the electric field of a point charge. 1. The field is directed radially outward from the charge. 2. The field has a magnitude that is constant for any given radius. 3. The field magnitude at radius r = 6 meters is 1/4 times the magnitude at 34 meters. While the first two given properties are general, the third property is a specific case of the 1/r* (read as "one over r squared") dependence of the electric field. In other words, the magnitude of the electric field of a point charge drops as the square of the radius. In this activity, you are going to use data to confirm this property. In your favorite spreadsheet program, plot the magnitude of the electric field ked, rz f'jlf at 0.5 m intervals. Here ke is the electrostatic constant and is equal to 8.99 x 107 N m?/C?, and as previously directed, q1 is +1 nC. If your spreadsheet program is capable of doing so, fit a power law curve to your calculated values. In Excel, you can access the dialog box shown below by right clicking on any data point and selecting "insert trendline.\" Now within the simulation, take data at intervals other than 0.5 meters. The intervals other than 0.5 meters will ensure that you can distinguish between the data and calculated values. Display both sets of data on a single graph. Do your data points match the calculated curve? How well does your data support the 1/r* dependence of the electric field magnitude on the radius? When writing your lab report or posting in the Discussion, be sure to include: Your data, in table format The corresponding graphical display Your answers to the questions posed above. When writing a lab report, this should be part of your discussion section and possibly included in your conclusion section. Part Il - Dipoles and Quadrupoles The principle of superposition is simply a statement that the electric field at any point is a sum of the contributions to the electric field from individual charges. The electric field is a vector quantity, so this sum requires some vector mathematics. Within the simulation, set up equal positive and negative charges (g) separated by some distance (d). This arrangement of charges is called an electric dipole, and as you might imagine, the resulting electric field is more complicated than that of the point charge. Take a few moments with the simulation, and use an E-Field sensor to explore the shape of the dipole field. Describe your observations in your laboratory notebook. Figure 2. A dipole consists of equal positive and negative charges (q) separated by some distance (d). In Figure 2 above, the green line indicates a set of points equidistant from both charges. Describe the magnitude and direction of the electric field along this line. Take the point directly between the two charges as the origin and the green line as the y axis. Calculate the magnitude of the electric field at 0.5 meter intervals along this axis. As with Part I, use a spreadsheet program to plot. Within the simulation, take data at intervals other than 0.5 meters. Display both set of data on a single graph. Do your data points match the calculated curve? Does the magnitude of the dipole field follow a power law? If so, is it the same or a different power law from that of the point charge? Four Charges: Take four charges and set up a quadrupole field. Here, your origin is the point directly in the center of the charges. Without calculation or graphing, investigate the magnitude of the electric field along the green axis. Compare your observations to the results from the dipole field. What might happen with even larger collections of electrically neutral collections of charges? When writing your lab report or posting in the Discussion, be sure to include Your data, in table format The corresponding graphical display Your answers to the questions posed above, both for dipoles and quadrupoles. When writing a lab report, this should be part of your discussion section and possibly included in your conclusion section. Figure 3. Four charges creating a quadrupole field