A2L Item 255

Goal: Hone the vector nature of the electric field

Source: CTQ283-5

Four
charges are positioned as shown. What is the direction of the
electrical field at the origin?

  1. Along i or in the +x direction
  2. Along j or in the +y direction
  3. Along -i or in the -x direction
  4. Along -j or in the -y direction
  5. Along some other direction
  6. E=0 at the origin

Commentary:

Answer

(6) Difficulty with this question usually indicates that students are
not familiar with vectors. Good follow up questions are to change the
sign of one or more charges.