A parallel-plate capacitor of area \(A\), plate separation \(d\) and capacitance \(C\) is filled with four dielectric materials having dielectric constants \(k_1, k_2,k_3\) and \(k_4\) as shown in the figure below. If a single dielectric material is to be used to have the same capacitance \(C\) in this capacitor, then its dielectric constant \(k\) is given by:
      

1. \( {k}={k}_1+{k}_2+{k}_3+3 {k}_4\)
2. \({k}=\frac{2}{3}\left({k}_1+{k}_2+{k}_3\right)+2 {k}_4\)
3. \({k}=\frac{2}{3} {k}_4\left(\frac{{k}_1}{{k}_1+{K}_4}+\frac{{k}_2}{{k}_2+{k}_4}+\frac{{k}_3}{{k}_3+{k}_4}\right)\)
4. \(\frac{1}{{k}}=\frac{1}{{k}_1}+\frac{1}{{k}_2}+\frac{1}{{k}_3}+\frac{3}{2 {k}_4}\)
Subtopic:  Dielectrics in Capacitors |
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NEET - 2016
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A dielectric slab of dielectric constant \(3\) having the same area of cross-section as that of a parallel plate capacitor but of thickness \({\frac{3}{4}}^{\text{th}}\) of the separation of the plates is inserted into the capacitor. The ratio of potential difference across the plates without dielectric to that with dielectric is:
1. \(1:2\)
2. \(2:3\)
3. \(3:2\)
4. \(2:1\)
Subtopic:  Dielectrics in Capacitors |
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From NCERT
NEET - 2024
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Two capacitors, each having a capacitance of \(40~\mu\text F\) are connected in series. The space between one of the capacitors is filled with a dielectric material of dielectric constant \(K,\) such that the equivalent capacitance of the system becomes \(24~\mu\text F.\) The value of \(K\) will be:
1. \(1.5\)
2. \(2.5\)
3. \(1.2\)
4. \(3\)
Subtopic:  Dielectrics in Capacitors |
 63%
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Given below are two statements: 
Assertion (A): In the absence of an externally applied electric field, the displacement per unit volume of a polar dielectric material is always zero.
Reason (R): In polar dielectrics, each molecule has a permanent dipole moment, but these dipoles are randomly oriented when there is no external electric field.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. Both (A) and (R) are False.
Subtopic:  Dielectrics in Capacitors |
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