Part I. Electric Field Lines and Flux Activity 1.1 Simulation of Electric Field Lines from Point Charges 1. Open the EMFIELD simulation by double-clicking its icon. Follow the instructions on the screen. Using the mouse, click on Sources on the menu bar and choose 3D point charges. Now click on Display and choose Show grid and Constrain to grid. Click and drag a point charge of relative mag- nitude +4 to a grid position near the center of the screen. 2. Click on Field & Potential on the menu bar and choose Field vectors. Move your cursor to a grid position two units to the right of the charge and click on the grid position. This vector represents the electric field at that point. 3. Now move your cursor to a grid position one unit to the left of the charge and click on this point. Sketch the results approximately to scale below and compare the length of the vectors (and the distance of the points from the charges) and their directions