https://phet.colorado.edu/sims/html/charges-and-fields/latest/charges-and-fields_all.html

SPH4U - Lesson 11 Part C Assignment Part 2: Electric Field Lines 1. Go to the Charges and Fields simulation site. Simulation 1: Two Point Charges (Same Charge) 2. Place two point charges, with the same charges (both positive or both negative), in a horizontal or vertical straight line. Place a sensor along the same line. Take a screen shot and include it with this assignment. 3. Using your measurements from the simulation, calculate the net Electric Field acting on the sensor. Include all of your steps. How close are the two values (use percentage error to express this value). 4. Repeat steps 2 and 4 but use different charges (one positive and one negative). Make sure to change the distance between the charges and the sensor