A Point Charge Q Is Placed on the X Axis

Multiple Choice

A point charge Q is placed on the x axis at x = 2.0 m. A second point charge, −Q, is placed at x = 3.0 m. If Q = 40 μC, what is the magnitude of the electrostatic force on a 30-μC charge placed at the origin?

A) 7.2 N
B) 3.9 N
C) 1.5 N
D) 14 N
E) 8.1 N