Question Detail
Question
Three point charges: q1=15μC at x=2m, q2=6μC at origin, resultant force on q3 (negative) is zero. x-coordinate of q3?
Correct Answer
Option A is the correct answer.
Detailed Explanation
For zero force on q3, forces from q1 and q2 cancel. k|q2 q3|/x² = k|q1 q3|/(2-x)² → 6/x² = 15/(2-x)² → (2-x)/x = √(15/6)=√2.5=1.581 → 2-x=1.581x → 2=2.581x → x=0.775 m.
Hint
Force balance: q2/x² = q1/(d-x)².