4. Drag and drop both a +1 nC and -1 nC charge onto the field. To begin, start with the negative charge closer to the top of the field and the positive charge closer to the bottom. Draw the resulting electric field around them. 5. Use the voltmeter to locate a "line" of zero potential difference and draw the line on your field map above. How do you explain the existence of zero electric potential where the electric field is NOT zero? ________________________________________ ____________________________________________________________________________________________________ ____________________________________________________________________________________________________ 6. Move the charges closer together and note what changes occur, particularly with respect to the field strength farther away from the source charges.: _______________________________________________________________________________ ____________________________________________________________________________________________________ 7. With the charges close enough to just touch each other, slowly move the voltmeter along the horizontal line located roughly along where the charges meet. What happens to the meter reading as you get nearer the edge of the field? ______________ ____________________________________________________________________________________________________ 8. Lay one source charge directly on top of the other. What happens to the field? _____________________________________ 9. What are the implications about field strength at a location far enough away from these source charges that they appear to be atop one another