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Capacitors

JEE Main level, numerical answer, medium

85 of 180

Question 85 of 180

A parallel plate capacitor with air between the plate has a capacitance of $15pF$ . The separation between the plate becomes twice and the space between them is filled with a medium of dielectric constant $3.5$ . Then the capacitance becomes $\dfrac{x}{4}pF$ . The value of $x$ is____.

Show answer and solution

Answer: 105

Capacitance of the parallel plate capacitor when air is present between the plates,

C=\dfrac{{\epsilon }_{0}A}{d}=15pF

Capacitance of the parallel plate capacitor when dielectric is filled in between the plates,

{C}^{'}=\dfrac{k{\epsilon }_{0}A}{{d}^{'}}=\dfrac{3.5{\epsilon }_{0}A}{2d}=\dfrac{3.5}{2}\times 15pF=\dfrac{105}{4}pF

Therefore,

x=105

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JEE Main 2025 Apr 2 Shift 1 question paper

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