Electric Field Lab - Distributed Charges Lab Group Members: This lab will use the phet simulation "Charges and Fields": https:/phet.colorado.edu/sims/html/charges-and-fields/latest/charges-and-fields_en.html We will be looking at a finite, uniform line charge and investigating when it can be modeled as an infinite uniform line charge. Experiment A. Electric Field Along y Axis 1. Go to the simulation and check "Values" and "Grid". Note the distance scale at the bottom. Place twenty-nine +1 nC point charges along the axis, evenly distributed over a length of 7.00 m. The point charges will start at x - -3.50 m and end at x = 3,50 m. Place the charges as far down as possible. See figure below. X = - 350 m X = 3.50 m 100000040000 060 0 00 0901 + X +1 nc Sensors 1 mater 2. Use the sensor to measure the electric field along the y-axis for values of y = 0.50 m. 1.00 m, 1.50 m, 2.00 m, 2.5 m 3.00 m, and 3.50 m. Record your results in an EXCEL table. These are your experimental values. Record your electric field values in units of N/C, not V/m. It is also best to use m, not cm for your y values. Electric Field Lab - PHYS 4103. Have EXCEL make a graph of Eexp (vertical axis) vs. y (horizontal axis). Follow the required graphing format. Your graph will not be linear. You do not need to do a linear regression as we are not linearizing this graph. 4. Now we will calculate the theoretical values of the electric field assuming it is an infinite line charge. Recall that the equation for the electric field of an infinite line charge is: E = 2KA y where ke is the electric constant and 2 is the linear charge density, 1 = 2 . For each y value in step 2, write an equation in EXCEL that will calculate the theoretical value of the electric field, using the equation above. 5. On the same graph using the experimental values, have EXCEL make a graph of Eth (vertical axis) vs. y (horizontal axis) for these theoretical values. Your graph will not be linear. You do not need to do a linear regression as we are not linearizing this graph. If you have done these correctly, it will look like the two graphs shown below. 160 0 140 0 120.0 100 0 40.0 20 0 0 0.5 1 15 2 25 3.5 y (om) 6. Now we will find the percent difference between your theoretical and experimental values. For each y value, have EXCEL calculate the percent difference. percent difference = theoretical - experimental xx 100% experimental Electric Field Lab - PHYS 4107. On the same graph, have EXCEL make a graph of percent difference (vertical axis) vs. y (horizontal axis). Your graph will not be linear. You do not need to do a linear regression as we are not linearizing this graph. If you have done these correctly, it will look like the three graphs shown below. 160.0 140.0 120.0 100.0 BO.D 20.0 0.5 15 2 2.5 3 3.5 Answer the following questions. 8. Look at your data table and graphs. Are the theoretical values and underestimate or an overestimate of the experimental values? 9. The infinite line charge equation is a valid approximation for a finite line charge if the points are close to the line charge. "Close" means the y coordinate of the point is much smaller than the length of the charge distribution. Mathematically, this means y