Two isolated point charges are fixed on an -axis in otherwise empty space
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Electric Force Field and Potential · Electric Force Field and Potential
Problem
Two isolated point charges are fixed on an x-axis in otherwise empty space. A charge of +5μC is located at x=−d/2, and an equal-magnitude charge of −5μC is located at x=+d/2. The surrounding region is to be represented using electric-field lines drawn in the plane containing the charges.
Complete the tasks below. Your responses should include clear verbal descriptions and, where requested, sketches labeled with all salient features.
(a) Sketch a representative electric-field line pattern for this charge configuration. Include at least eight lines emerging from or terminating on each charge, show the correct sense (arrow direction), and indicate any symmetry you use.
(b) Justify the relative number of lines you drew for each charge and explain how your sketch reflects the equality of their magnitudes and the opposite signs.
(c) Determine whether there exists a point on the x-axis, other than at infinity, where the net electric field is zero. If such a point exists, identify its location relative to the charges and explain your reasoning based on your field-line sketch.
(d) Describe how the density and curvature of your field lines change as one moves along the y-axis (perpendicular bisector of the line joining the charges) from the midpoint between the charges to a point far away. Relate these changes to variations in electric-field magnitude.