JEE Main 2024 Physics question
Two identical conducting spheres P and S with charge Q on each, repel each other with a force 16N. A third identical uncharged conducting sphere R is successively brought in contact with the two spheres. The new force of repulsion between P and S is:
Answer: (B)
Solution
After touching P, R and P hold Q/2 each; then R touches S: (Q/2 + Q)/2 = 3Q/4 each. F ∝ (Q/2)(3Q/4) = 3Q²/8, so F = 16 × 3/8 = 6 N.