Two point charges of magnitudes + 8.00 $\mu$C, and + 10.0 $\mu$C are placed along the x-axis at x = 0 cm and x = 100 cm, respectively. Where must a third charge be placed along the x-axis so that it does not experience any net force because of the other two charges?
A) 47.2 cm
B) 50 cm
C) 91.2 cm
D) 9.12 cm
E) 4.72 cm

Question

Quizplus · Accepted Answer

For the third charge to experience no net force, it must be placed closer to the smaller charge due to the inverse square law of electrostatic force. The exact position can be found using the equation for electrostatic force, $F = k \frac{|q_1q_2|}{r^2}$, and setting the forces due to each charge equal to each other to solve for the position. The correct calculation leads to the position being 47.2 cm from the +8.00 $\mu$C charge, placing it between the two charges but closer to the smaller one.

Two Point Charges of Magnitudes + 8 μ\muμ C, and + 10

Two Point Charges of Magnitudes + 8 $\mu$ C, and + 10