1
JEE Main 2026 (Online) 21st January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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

A

$\frac{3 C K^2}{(2 K+1)^2}$

B

$\frac{4 K C}{3 K-1}$

C

$\frac{C K}{2+K}$

D

$\frac{3 K C}{2 K+1}$

2
JEE Main 2025 (Online) 4th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Three parallel plate capacitors $C_1, C_2$ and $C_3$ each of capacitance $5 \mu \mathrm{~F}$ are connected as shown in figure. The effective capacitance between points $A$ and $B$, when the space between the parallel plates of $C_1$ capacitor is filled with a dielectric medium having dielectric constant of 4, is :

JEE Main 2025 (Online) 4th April Evening Shift Physics - Capacitor Question 16 English

A
$9 \mu \mathrm{~F}$
B
$30 \mu \mathrm{~F}$
C
$7.5 \mu \mathrm{~F}$
D
$22.5 \mu \mathrm{~F}$
3
JEE Main 2025 (Online) 3rd April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Using a battery, a 100 pF capacitor is charged to 60 V and then the battery is removed. After that, a second uncharged capacitor is connected to the first capacitor in parallel. If the final voltage across the second capacitor is 20 V , its capacitance is: (in pF )
A
600
B
100
C
400
D
200
4
JEE Main 2025 (Online) 3rd April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A parallel plate capacitor is filled equally(half) with two dielectrics of dielectric constants $\varepsilon_1$ and $\varepsilon_2$, as shown in figures. The distance between the plates is $d$ and area of each plate is $A$. If capacitance in first configuration and second configuration are $\mathrm{C}_1$ and $\mathrm{C}_2$ respectively, then $\frac{C_1}{C_2}$ is:

First Configuration

JEE Main 2025 (Online) 3rd April Morning Shift Physics - Capacitor Question 17 English 1

Second Configuration

JEE Main 2025 (Online) 3rd April Morning Shift Physics - Capacitor Question 17 English 2

A
$\frac{\varepsilon_0\left(\varepsilon_1+\varepsilon_2\right)}{2}$
B
$\frac{\varepsilon_1 \varepsilon_2^2}{\left(\varepsilon_1+\varepsilon_2\right)^2}$
C
$\frac{4 \varepsilon_1 \varepsilon_2}{\left(\varepsilon_1+\varepsilon_2\right)^2}$
D
$\frac{\varepsilon_1 \varepsilon_2}{\varepsilon_1+\varepsilon_2}$

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