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JEE Main 2026 (21 Jan, Shift 1) · Dielectrics

Dielectrics question from JEE Main 2026 (21 Jan, Shift 1)

Q10JEE Main 2026 · 21 JAN · SHIFT 1Easy

Dielectrics

A parallel plate capacitor has capacitance CC, when there is vacuum within the parallel plates. A sheet having thickness (13)rd\left(\frac{1}{3}\right)^{\text{rd}} of the separation between the plates and relative permittivity KK is introduced between the plates. The new capacitance of the system is:

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Answer: (d)

  1. C′=ε0Ad−t+tKC' = \frac{\varepsilon_0 A}{d - t + \frac{t}{K}} with t=d3t = \frac{d}{3}.
  2. 2d3+d3K=d(2K+1)3K\frac{2d}{3} + \frac{d}{3K} = \frac{d(2K+1)}{3K}.
  3. C′=3KC2K+1C' = \frac{3KC}{2K+1}.
  4. So the answer is (d).
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