JEE Main 2024PhysicsCapacitanceHardNumerical

JEE Main 2024 — Capacitance Question with Solution

JEE Main 2024 (31 Jan Shift 1)

Question

A parallel plate capacitor with plate separation 5 mm is charged up by a battery. It is found that on introducing a dielectric sheet of thickness 2 mm, while keeping the battery connections intact, the capacitor draws 25% more charge from the battery than before. The dielectric constant of the sheet is ____.

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Show full solutionCorrect answer: 2
Correct answer
2

Step-by-step explanation

Without dielectric, capacitance will be C=Aε0d.

Therefore, charge on it, Q=Aε0dV

Now, with dielectric capacitance will be C'=Aε0d-t+tK.

Hence, charge on it will be Q'=Aε0Vd-t+tK

Given:

Aε0Vd-t+tK=1.25Aε0Vd

⇒1.253+2K=5

⇒K=2

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About this question

This is a previous-year question from JEE Main 2024, covering the Capacitance chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.