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NEET2026PhysicsChapterActual

A parallel plate air capacitor has an initial capacitance of 12 pF . If the separation between its plates is reduced to one-third of its original value and the area of each plate is doubled, what will be the new capacitance?

Options

  1. A72 pF
  2. B8 pF
  3. C18 pF
  4. D2 pF

Correct answer

A. 72 pF

Step-by-step solution

The capacitance of a parallel plate capacitor is given by C = ₀ A d Given initial capacitance C₁ = ₀ A d = 12 pF The new area is A' = 2A and the new separation is d' = d 3 The new capacitance is C₂ = ₀ A' d' = ₀ (2A) d 3 = 6 ₀ A d C₂ = 6 C₁ = 6 12 pF = 72 pF Answer: 72 pF

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