JEE Mains · Physics · STD 12 - Electric potential and capacitance
- JEE Mains 2026
- Easy
- MCQ
Three parallel plate capacitors each with area A and separation d are filled with two dielectric ( \(k _1\) and \(k _2\) ) in the following fashion. Which of the following is true? \(\left( k _1> k _2\right)\)

Pick an option to check your answer.
Answer & Solution
Correct Answer
(D) \(C_{A}>C_{C}>C_{B}\)
Step-by-step Solution
Detailed explanation
For \(C_A\) :

Let \(\frac{\varepsilon_0 A}{ d }= C\)
\(\therefore \quad C _{ A }=\frac{ K _1 C }{2}+\frac{ K _1 K_2 C }{ K _1+ K _2}\)
\(= K _1 C \left[\frac{ K _1+2 K_2}{2\left(K_1+ K _2\right)}\right]\)
For \(C _{ B }\) :

\(C _{ B }=\frac{ K _2 C }{2}+\frac{ K _1 K_2 C }{ K _1+ K _2}\)
\(= K _2 C \left[\frac{ K _1+2 K_2}{2\left(K_1+ K _2\right)}\right]\)
For \(C _{ C }\) :

\(C _{ C }=\frac{2 K_1 K_2 C }{\left( K _1+ K _2\right)}\)
\(C_A>C_C>C_B\)

Let \(\frac{\varepsilon_0 A}{ d }= C\)
\(\therefore \quad C _{ A }=\frac{ K _1 C }{2}+\frac{ K _1 K_2 C }{ K _1+ K _2}\)
\(= K _1 C \left[\frac{ K _1+2 K_2}{2\left(K_1+ K _2\right)}\right]\)
For \(C _{ B }\) :

\(C _{ B }=\frac{ K _2 C }{2}+\frac{ K _1 K_2 C }{ K _1+ K _2}\)
\(= K _2 C \left[\frac{ K _1+2 K_2}{2\left(K_1+ K _2\right)}\right]\)
For \(C _{ C }\) :

\(C _{ C }=\frac{2 K_1 K_2 C }{\left( K _1+ K _2\right)}\)
\(C_A>C_C>C_B\)
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