Electric field is developed between the parallel plates of the capacitor when plates are connected across a battery. This setup is known as the parallel plate capacitor.

Parallel plate capacitor formula is

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Important Parallel Plate Capacitor Questions with Answers

1. Choose the correct answer: The two plates of parallel plate capacitors are ______

1. Unequal in length
2. Equal in length

Answer: b) Equal in length

Explanation: Parallel plates of the capacitor are equal in dimension.

2. Which relation is correct.

1. Q ∝ 1/V
2. Q ∝ 2V
3. Q ∝ V
4. Q ∝ V/2

Answer: c) Q ∝ V

Explanation: Q ∝ V since the potential difference between the two plates of a parallel plate capacitor is directly proportional to the number of electric charges stored in any of the plates.

3. Is mica a conducting material?

1. YES
2. NO

Answer: a) YES

Explanation: Mica is a non-conducting material.

4. The permittivity of space is _______

1. 2.854 × 10⁻¹² F/m
2. 4.854 × 10⁻¹² F/m
3. 6.854 × 10⁻¹² F/m
4. 8.854 × 10⁻¹² F/m

Answer: d) 8.854 × 10⁻¹² F/m

Explanation: ϵo is the permittivity of space, and the value permittivity is 8.854 × 10⁻¹² F/m.

5. The relative permittivity of dielectric material is represented by ______

1. r
2. p
3. k
4. d

Answer: c) k

Explanation: The ratio of the capacitance of a capacitor using that material as a dielectric, compared with a similar capacitor that has vacuum as its dielectric.

6. The parallel plate capacitor formula is _______

1. \(\begin{array}{l}C=k\epsilon _{0}\frac{A}{d}\end{array} \)
2. \(\begin{array}{l}C=k _{0}\frac{d}{A}\end{array} \)
3. \(\begin{array}{l}C=k\epsilon _{0}+\frac{A}{d}\end{array} \)
4. \(\begin{array}{l}C=k\epsilon _{0}-\frac{A}{d}\end{array} \)

Answer: a)

Explanation: The parallel plate capacitor is given by the formula

7. The relative permittivity for air is ______

1. 1
2. 2
3. 4
4. 6

Answer: a) 1

Explanation: The relative permittivity for air is 1.00058.

8. The capacitance for the parallel plate capacitor is _______

1. \(\begin{array}{l}C=\frac{\varepsilon _{0}d}{A}\end{array} \)
2. \(\begin{array}{l}C=\frac{V}{Q}= {\varepsilon _{0}A}+{d}\end{array} \)
3. \(\begin{array}{l}C=\frac{V}{Q}= {\varepsilon _{0}A}-{d}\end{array} \)
4. \(\begin{array}{l}C=\frac{Q}{V}=\frac{\varepsilon _{0}A}{d}\end{array} \)

Answer: d)

Explanation: The capacitance for the parallel plate capacitor can be given as

9. Units of capacitance are ______

1. Farad
2. Pico-farads (pF)
3. Micro-farads (µF)
4. All the above options

Answer: d) All the above options

Explanation: Farads, micro-farads (µF), and pico-farads (pF) are the units of capacitance.

10. State true or false: The two conducting plates of parallel plate capacitors act as electrodes.

1. True
2. False

Answer: a) True

Explanation: The two conducting plates of parallel plate capacitors behave as electrodes and there is dielectric between the plates.

Practice Questions

1. What is a capacitor?
2. What are the types of capacitors?
3. What is meant by a parallel plate capacitor?
4. Define dielectric.
5. Explain conducting and non-conducting materials with examples.