PHYS 421 Electric Field Lab Lab Group Members: This lab will use the phet simulation \"Charges and Fields": https:fx'phctxolorado.edur'simsrhtmlt'chargos-and-t'icldsflatchchargcs-and-clds_en.htm1 Experiment A. Collecting Data 1. Go to the simulation and check \"Values" and \"Grid". Check the distance scale at the bottom. Place two +1 nC charges separated by 4.0 m as shown in the gure. '2. You will be using a sensor to measure the electric field along the X axis. You will place the sensor at various locations on the x axis for x 2 m and record the value of the electric eld in units of MC. Use the x values shown below. Record your results in an EXCEL table. **Note that the simulation gives the magnitude of the eld so add a negative sign when the electric field vector points to the left.\" Re _ion Data Points 1: 2 m .r = 2.4. 2.6. 2.8. 3.0. 3.5. 4.0 In Electric Field Lab - PHYS 410 l 3. Have EXCEL make a graph of E (vertical axis) vs. .1: (horizontal axis). Using EXCEL's graph as a guide, hand draw a graph. No numbers necessary just the correct shapes in all three regions. Be sure to locate the asymptotes and draw them on the graph. You do not need to do a linear regression as we are not linearizing the graph. 4. Replace the +1 nC charge on the right with a -1 HC charge and repeat steps 2 and 3. B. Answer the following questions. 1. For the rst graph. why are there vertical asymptotes at x = -2.0 m and at x = +2.0 m'? Id 1 r Hint: Use the point charge equation, E = k, and recall mathematically how you get a vertical asymptote. 2. For the rst graph, why is the electric eld always negative when x 2.0 m? 4. For the second graph, why is the electric field always positive when -2.0 m 0.5 m region 2 region 3 % mo V C SCH 501' 0.5 in Start with the sensor in region 1 and move it along the x axis until the sensor reads near zero. Look for when the electric field vector reverses its direction; this will be where the field is zerof Be sure to move the sensor through all three regions. Exclude the x = icosolutions. At what value of x is the electric field zero? In recording your answer for x, remember that x = 0 is at the location of the +2 nC charge. Electric Field Lab - PHYS 410 3 2. In this part you will mathematically calculate the magnitude of the electric field by the 2 nC and the -1 nC charge at the x value you found in in the previous step. You will use the equation electric field equation for a point charge: E = k. : the x value in the previous step and the r value in the given equation are not necessarily the same. The r value in the equation is the distance from the charge to the point you are finding the electric field. Find the electric field produced by the +2 nC charge at the location you found in the previous step. Give answer using i notation . Find the electric field produced by the -1 nC charge at the location you found in the previous step. Give answer using i notation . What is the sum of these two vectors? It should be close to zero. tric Field Lab - PHYS 410 43. Repeat the previous step but this time using the charge arrangement shown in the gure. region I region 2 region 3 6 move sensor 3.0 m 4. Repeat step 2 for the charge arrangement in the previous step. Electric Field Lab - PHYS 410 5 Answer the following questions. 5. For the charge arrangement in C1, why can't the location of zero field be in region 2? Hint: Look at the direction of the field made by both charges in this region. Can these fields add to zero? region 1 region 2 region 3 +2 nc -1 nc move sensor 0.5m 6. For the charge arrangement in C1, why is the location of zero field closer to -1 nC charge rather than closer to the +2 nC charge? Hint: Look at the role of q and r in the electric field equation for a point charge. 7. For the charge arrangement in C3, why can't the location of zero field be in region 1 or region 3? +1 nc +2 nc move sensor 3.0m 8. For the charge arrangement in C3, why is the location of zero field closer to +1 nC charge rather than closer to the +2 nC charge? You will turn in the following: 1. This handout 2. EXCEL Data Tables - follow proper Electric Field Lab - PHYS 410 6 format. 3. EXCEL Graphs - follow proper format. 4. Your Hand Graphs