일반물리학 2 — Electric Fields: Problem 49

49 Figure 22-43 shows two charged particles on an x axis: $-q = -3.20 \times 10^{-19}\text{ C}$ at $x = -3.00\text{ m}$ and $q = 3.20 \times 10^{-19}\text{ C}$ at $x = +3.00\text{ m}$. What are the (a) magnitude and (b) direction (relative to the positive direction of the x axis) of the net electric field produced at point P at $y = 4.00\text{ m}$? (c) What is the magnitude of the net field if y is doubled?