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NEET2026PhysicsChapterActual

Two identical small conducting spheres P and Q carry charges of +8 C and -2 C respectively. When placed at a certain distance r apart in vacuum, the magnitude of the attractive electrostatic force between them is F . A third identical conducting sphere R carrying an initial charge of +4 C is brought into contact with sphere P first, then with sphere Q , and finally removed. If the distance between P and Q remains unc

Options

  1. AF 4
  2. B9F 8
  3. C3F 4
  4. D4F 3

Correct answer

C. 3F 4

Step-by-step solution

Initial charges on the spheres are q_P = +8 C and q_Q = -2 C . The initial electrostatic force between P and Q is: F = k |q_P| |q_Q| r^2 = k (8)(2) r^2 = 16k r^2 When the identical sphere R with charge q_R = +4 C is brought into contact with P , they share the total charge equally: q_P' = q_R' = q_P + q_R 2 = 8 + 4 2 = +6 C Next, sphere R (now carrying +6 C ) is brought into contact with Q (carrying -2 C ). They share the total charge equally: q_Q' = q_R'' = q_R' + q_Q 2 = 6 + (-2) 2 = +2 C The new charges on P and

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