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MHT CET202525 Apr 2025Morning ShiftPhysicsElectrostaticsActual

Two point charges q ₁ and q ₂ are ' l ' distance apart. If one of the charges is doubled and distance between them is halved. The magnitude of force becomes n times, where n is

Options

  1. A1
  2. B2
  3. C8
  4. D16

Correct answer

C. 8

Step-by-step solution

Let the initial charges be q₁ and q₂ , separated by a distance l . The initial force magnitude is F₁ = k |q₁ q₂| l^2 . When one charge is doubled ( q₁' = 2q₁ ) and the distance halved ( l' = l/2 ), the new force becomes: F₂ = k |q₁' q₂'| (l')^2 = k |(2q₁) q₂| (l/2)^2 Simplifying: F₂ = k 2|q₁ q₂| l^2/4 = k 2|q₁ q₂| l^2 4 = 8 (k |q₁ q₂| l^2 ) = 8F₁ The final force magnitude is 8 times the original force. The correct option is C.

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