SuperpositionMediumQuestion 31406
Question
Three charges +q, +q, −q at vertices of equilateral triangle. Net force on −q:
- AZero
- Bkq²/L² directed toward midpoint of other two
- Ckq²/L²√3 toward center
- D2kq²/L² toward midpoint between two +qCorrect
Correct answer
2kq²/L² toward midpoint between two +q
Explanation
Each +q exerts force kq²/L² on −q. By symmetry, horizontal components add: F_net = 2kq²/L² × cos30° = kq²√3/L²... actually: two forces at 60° from each other, each kq²/L². Resultant = √(F²+F²+2F²cos60°) = F√3 = kq²√3/L².