Two charges Q₁ = -3 μC and Q₂ = +3 μC are located on the y-axis at y₁ = -5 cm and y₂= +5 cm respectively. A third charge Q₃ = +24 μC is added on the y-axis so that the electric field at the origin is equal to zero. What is the position of Q₃?

Question

Quizplus · Accepted Answer

The electric field at the origin due to Q1 and Q2 cancels each other out because they are equal in magnitude and opposite in direction. To make the total electric field zero, Q3 must be placed such that its field cancels the net field from Q1 and Q2. Given Q3 is larger, it should be placed further away from the origin on the negative y-axis, at y3 = -10 cm.

Two Charges Q1 = -3 μC and Q2 = +3

Two Charges Q₁ = -3 μC and Q₂ = +3