1. a) Sketch arrows on the diagram to indicate the direction of the electric field, if any, at each of the points A, B, C, and D.
A positively charged test particle is observed to move as described below. For each motion, tell whether the work done by the electric field is positive, negative, or zero. Explain your reasoning in each case. 4. Two charges +Q and -Q are fixed in place at the positions shown. Four points A, B, C, and D are labeled on the diagram.
b)
• The test charge moves from point B to point A
• The test charge moves from point B to point C
• The test charge moves from point B to point D
2. For each pair of charges, draw a force vector on each charge to show the electric force acting on that charge. The length of each vector should be proportional to the magnitude of the force. Each (+) and (-) symbol represents the same quantity of charge.
3. For each of the figures, use dots to mark any point or points (other than infinity) where the electric field is zero. Explain your reasoning for part (a).
