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Q. No.| 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 are randomly oriented in the absence of an externally applied 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. |
A parallel plate capacitor with air between the plates has a capacitance of \(8~\text{pF}\). What will be the capacitance if the distance between the plates is reduced by half, and the space between them is filled with a substance of dielectric constant \(6\)?
1. \(48~\text{pF}\)
2. \(8~\text{pF}\)
3. \(96~\text{pF}\)
4. \(60~\text{pF}\)
| (I) | The charge on the plates |
| (II) | The potential difference between the plates |
| (III) | The energy stored in the capacitor |
| 1. | (I) only | 2. | (I), (II) |
| 3. | (I), (III) | 4. | (I), (II), (III) |
| 1. | \(1 \) m2 | 2. | \(0.45 \) m2 |
| 3. | \(1.5 \) m2 | 4. | \(1.2 \) m2 |
| Assertion (A): | A charged parallel plate capacitor is filled with dielectric as shown in the figure. If \(K_1:K_2 = 2:1\) then \(E_1:E_2= 1:2.\)  |
| Reason (R): | Electric field intensity is directly proportional to the dielectric constant. |
| 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. |
The capacitance of a parallel plate capacitor with air as a medium is \(6~\mu\text{F}\). With the introduction of a dielectric medium, the capacitance becomes \(30~\mu\text{F}\). The permittivity of the medium is:\(\left(\varepsilon_0=8.85 \times 10^{-12} ~\text{C}^2 \text{N}^{-1} \text{m}^{-2}\right )\)
| 1. | \(1.77 \times 10^{-12}~ \text{C}^2 \text{N}^{-1} \text{m}^{-2}\) | 2. | \(0.44 \times 10^{-10} ~\text{C}^2 \text{N}^{-1} \text{m}^{-2}\) |
| 3. | \(5.00 ~\text{C}^2 \text{N}^{-1} \text{m}^{-2}\) | 4. | \(0.44 \times 10^{-13} ~\text{C}^2 \text{N}^{-1} \text{m}^{-2}\) |
1. \(1:2\)
2. \(2:3\)
3. \(3:2\)
4. \(2:1\)
A dielectric slab is inserted between the plates of an isolated charged capacitor. Which of the following quantities will remain the same?
| (a) | the electric field in the capacitor |
| (b) | the charge on the capacitor |
| (c) | the potential difference between the plates |
| (d) | the stored energy in the capacitor |
Choose the correct option:
1. (a), (b)
2. (b) only
3. (c), (a)
4. (a), (d)
1. \(1.5\)
2. \(2.5\)
3. \(1.2\)
4. \(3\)
A parallel plate capacitor with cross-sectional area \(A\) and separation \(d\) has air between the plates. An insulating slab of the same area but the thickness of \(\dfrac{d}{2}\) is inserted between the plates as shown in the figure having a dielectric constant, \(K=4\). The ratio of new capacitance to its original capacitance will be:
| 1. | \(2:1\) | 2. | \(8:5\) |
| 3. | \(6:5\) | 4. | \(4:1\) |
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Q. No.
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