Capacitance: Definition, Types, and Applications

Question 1

When a dielectric material with dielectric constant κ is inserted between the plates of a parallel-plate capacitor, how does the energy stored in the capacitor change?

Accepted Answer

Increases by a factor of κ

Answer

No change

Answer

Decreases by a factor of κ

Answer

Increases by a factor of κ^2

Question 2

What is the main purpose of capacitors in electrical circuits?

Accepted Answer

Storing electrical energy

Answer

Blocking current flow

Answer

Boosting voltage signals

Answer

Producing alternating current

Question 3

Which formula accurately expresses the capacitance (C) of a parallel-plate capacitor?

Accepted Answer

C = εA/d

Answer

C = Q/V

Answer

C = V/Q

Answer

C = Qd/εA

Question 4

When considering the energy (E) stored in a capacitor, which equation accurately represents this value?

Accepted Answer

E = 1/2 CV²

Answer

E = CV

Answer

E = 1/2 V²C

Answer

E = V²C

Question 5

Which of the listed applications is not a typical use of capacitors in electrical engineering?

Accepted Answer

Amplification

Answer

Energy storage

Answer

Filtering

Answer

Timing circuits

Question 6

Enlarging the plate area of a capacitor will result in what change to its capacitance?

Accepted Answer

Increase

Answer

Decrease

Answer

Remain unchanged

Answer

Change unpredictably

Question 7

Among the listed types of capacitors, which one possesses variable capacitance?

Accepted Answer

Variable capacitor

Answer

Electrolytic capacitor

Answer

Ceramic capacitor

Answer

Film capacitor

Question 8

In the International System of Units (SI), what unit is used to measure capacitance?

Accepted Answer

Farad

Answer

Henry

Answer

Ohm

Answer

Volt

Question 9

The primary function of a dielectric in a capacitor is to:

Accepted Answer

Prevent electrical breakdown

Answer

Enhance capacitance

Answer

Store energy

Answer

Reduce resistance

Question 10

A parallel-plate capacitor has plates with a fixed area. What happens to its capacitance if the distance between the plates is reduced while the charge remains constant?

Accepted Answer

Increases

Answer

Decreases

Answer

Stays the same

Question 11

Which of the following best defines Capacitance?

Accepted Answer

The ability of a component to store electrical energy in an electric field.

Answer

The amount of electric current flowing through a component.

Answer

The resistance offered by a component to the flow of electric current.

Question 12

Which of the following materials is commonly used as a dielectric in capacitors?

Accepted Answer

Ceramic

Answer

Silver

Answer

Copper

Answer

Aluminum

Question 13

The energy (E) stored in a capacitor with capacitance (C) and voltage (V) is given by:

Accepted Answer

E = 1/2 CV^2

Answer

E = V^2/C

Answer

E = CV

Answer

E = C^2/V

Question 14

Which of the following is NOT an application of capacitors?

Accepted Answer

Power generation

Answer

Timing circuits

Answer

Filtering

Answer

Energy storage

Question 15

A 220 μF capacitor is charged to a voltage of 12 V. What is the stored charge on the capacitor?

Accepted Answer

2.64 mC

Answer

4.48 mC

Answer

1.1 mC

Question 16

Which circuit element stores energy in an electric field?

Accepted Answer

Capacitor

Answer

Inductor

Answer

Resistor

Question 17

As the voltage across a capacitor increases, what happens to the electric field between its plates?

Accepted Answer

It increases

Answer

It decreases

Answer

It reverses

Answer

It remains the same

Question 18

What is the SI unit of capacitance?

Accepted Answer

Farad

Answer

Volt

Answer

Coulomb

Answer

Ohm

Question 19

Which of the following is the SI unit of capacitance?

Accepted Answer

Farad (F)

Answer

Coulomb (C)

Answer

Ohm (Ω)

Answer

Henry (H)

Question 20

Which of the following factors does NOT affect the capacitance of a parallel-plate capacitor?

Accepted Answer

Plate thickness

Answer

Plate separation

Answer

Plate area

Answer

Dielectric permittivity

Question 21

Which of the following applications of capacitors utilizes their ability to store electrical charge?

Accepted Answer

Energy storage in electronic devices

Answer

Smoothing voltage ripples

Answer

Filtering AC signals

Answer

Tuning resonant circuits

Question 22

A capacitor is connected in series with a resistor to form an RC circuit. What action will increase the time constant of this circuit?

Accepted Answer

Increasing both capacitance and resistance

Answer

Decreasing both capacitance and resistance

Answer

Increasing capacitance only

Answer

Increasing resistance only

Question 23

Which of the following materials is NOT a suitable dielectric for a capacitor?

Accepted Answer

Metal

Answer

Plastic

Answer

Ceramic

Answer

Paper

Question 24

In a series combination of capacitors, the equivalent capacitance is:

Accepted Answer

Less than the smallest capacitance

Answer

Equal to the sum of the capacitances

Answer

Equal to the average of the capacitances

Answer

Greater than the largest capacitance

Question 25

Which of the following materials is a **non-polar** dielectric material?

Accepted Answer

Ceramic

Answer

Tantalum

Answer

Electrolytic capacitor

Answer

Aluminum

Question 26

The capacitance of a cylindrical capacitor with inner radius 'a' and outer radius 'b' is given by:

Accepted Answer

2πε₀L / ln(b/a)

Answer

2πε₀L(b - a)

Answer

πε₀(b - a) / ln(b/a)

Answer

πε₀L / ln(a/b)

Question 27

Which of the following factors **increases** the capacitance of a capacitor?

Accepted Answer

Using a dielectric material with higher permittivity

Answer

Increasing the distance between plates

Answer

Decreasing the plate area

Answer

Increasing the voltage applied

Question 28

In a parallel combination of capacitors, the total voltage across the capacitors is:

Accepted Answer

Equal to the voltage across each individual capacitor

Answer

Greater than the voltage across the capacitor with the largest capacitance

Answer

Less than the voltage across the capacitor with the smallest capacitance

Question 29

Which of the following is the unit of capacitance?

Accepted Answer

Farad (F)

Answer

Henry (H)

Answer

Coulomb (C)

Answer

Volt (V)

Question 30

The capacitance of a capacitor is 100 μF. If the charge stored on the capacitor is doubled, the voltage across the capacitor will:

Accepted Answer

Increase by a factor of 2

Answer

Increase by a factor of 4

Answer

Decrease by a factor of 2

Answer

Remain the same

Question 31

Which of the following is the definition of capacitance?

Accepted Answer

The ability of a conductor to store electrical charge

Answer

The amount of electrical energy stored in a capacitor

Answer

The resistance to the flow of electrical current

Question 32

What is the SI unit of capacitance?

Accepted Answer

Farad

Answer

Volt

Answer

Coulomb

Answer

Ohm

Question 33

Which of the following is NOT a type of capacitor?

Accepted Answer

Wirewound capacitor

Answer

Ceramic capacitor

Answer

Parallel-plate capacitor

Answer

Electrolytic capacitor

Question 34

What is the capacitance of a parallel-plate capacitor with plate area A, plate separation d, and permittivity ε?

Accepted Answer

εA/d

Answer

Ad/ε

Answer

dε/A

Answer

εd/A

Question 35

What is the energy stored in a capacitor with capacitance C and voltage V?

Accepted Answer

1/2CV^2

Answer

C/V^2

Answer

CV^2

Answer

1/2CV

Question 36

What is the effect of connecting two capacitors in parallel?

Accepted Answer

The total capacitance increases

Answer

The voltage across each capacitor increases

Answer

The total capacitance decreases

Answer

The total capacitance remains the same

Question 37

What is the purpose of a dielectric material in a capacitor?

Accepted Answer

To increase the capacitance and prevent short circuits

Answer

To decrease the capacitance and increase insulation

Answer

To provide a conducting path for electrical current

Question 38

Which of the following factors does NOT affect the capacitance of a capacitor?

Accepted Answer

Temperature

Answer

Plate separation

Answer

Permittivity of the dielectric

Answer

Plate area

Question 39

Which of the following is the unit of capacitance?

Accepted Answer

Farad (F)

Answer

Volt (V)

Answer

Coulomb (C)

Answer

Ohm (Ω)

Question 40

Which of the following materials is a good dielectric?

Accepted Answer

Rubber

Answer

Copper

Answer

Salt water

Answer

Steel

Question 41

What is the energy stored in a capacitor?

Accepted Answer

1/2 CV^2

Answer

V^2/C

Answer

CV

Answer

C/V^2

Question 42

An ideal capacitor is connected to a battery. What is the charge on the capacitor?

Accepted Answer

CV

Answer

V/C

Answer

1/CV

Answer

C/V

Question 43

Capacitors are used in electronic circuits for which of the following purposes?

Accepted Answer

Storing charge, filtering signals, and smoothing voltage

Answer

Generating oscillations

Answer

Amplifying signals

Question 44

What is the capacitance of a capacitor with n identical parallel plates, each with area A and separation d?

Accepted Answer

nπεA/d

Answer

nπεAd

Answer

πεAn/d

Answer

πεA/nd

Question 45

What is the capacitance of a parallel-plate capacitor with plates of area 2 m² separated by a distance of 1 mm in air? (ε₀ = 8.85 x 10⁻¹² F/m)

Accepted Answer

17.7 nF

Answer

35.4 nF

Answer

8.85 pF

Answer

177 pF

Question 46

Which of the following is NOT a factor that affects the capacitance of a capacitor?

Accepted Answer

Charge on the plates

Answer

Area of the plates

Answer

Dielectric material between the plates

Answer

Distance between the plates

Question 47

What is the energy stored in a 10 μF capacitor charged to a potential difference of 100 V?

Accepted Answer

50 mJ

Answer

5 mJ

Answer

1 J

Answer

100 mJ

Question 48

A capacitor stores 0.2 J of energy when charged to a potential difference of 50 V. What is its capacitance?

Accepted Answer

160 μF

Answer

800 μF

Answer

400 μF

Answer

80 μF

Question 49

What is the equivalent capacitance of three 10 μF capacitors connected in series?

Accepted Answer

3.33 μF

Answer

20 μF

Answer

10 μF

Answer

30 μF

Question 50

What happens to the capacitance of a parallel-plate capacitor when a dielectric material with a dielectric constant of 4 is inserted between its plates?

Accepted Answer

It increases by a factor of 4.

Answer

It increases by a factor of 2.

Answer

It remains the same.

Answer

It decreases by a factor of 4.

Question 51

Which of the following is a common application of capacitors in electrical engineering?

Accepted Answer

All of the above

Answer

Smoothing out voltage fluctuations

Answer

Storing energy in power supplies

Answer

Filtering out unwanted frequencies in circuits

Question 52

Two capacitors with capacitances of 5 μF and 10 μF are connected in parallel. What is their equivalent capacitance?

Accepted Answer

15 μF

Answer

50 μF

Answer

7.5 μF

Answer

2.5 μF

Question 53

A capacitor is charged with a constant current of 2 mA for 5 seconds. If the final voltage across the capacitor is 10 V, what is its capacitance?

Accepted Answer

1 mF

Answer

10 mF

Answer

2 mF

Answer

0.5 mF

Question 54

A variable capacitor has a capacitance that can be adjusted from 10 pF to 100 pF. What is the purpose of using a variable capacitor in a circuit?

Accepted Answer

To tune the circuit to a specific frequency

Answer

To block DC current

Answer

To store a fixed amount of energy

Answer

To amplify the input signal