15.3. Electrostatic Fields http://www.ck12.org
FIGURE 15.18
- A 90. 0 μCcharge is placed in an electric field at a point where the magnitude of the electric field is equal to
- 20 × 105 NC. What is the magnitude of the electrostatic force acting on the charge?
Answer: We Use the equationF=qE= ( 90. 0 × 10 −^6 C)
(
5. 20 × 105 NC
)
= 46. 8 N
Illustrative Example 15.3.1
A positive test chargeq′is placed in the field of the positive charge+Qand negative charge−Qas seen inFigure
15.19. Draw the forces acting onq′.
FIGURE 15.19
Answer:
The charge−Qattractsq′with a smaller force than+Qrepels it, since it is farther from the test chargeq′than the
positive charge+Q. The forces that−Qand+Qplace uponq′are shown dashed. The net force, drawn solid, is
shown as the vector sum of the two dashed vectors. The curved line represents one of the lines of force between the
positive and negative charges.