Inductors and Capacitors in AC Circuits: Interactive Learning Quizzes

Question 1

How is the capacitive reactance of a capacitor in an AC circuit calculated?

Accepted Answer

XC = 1/(2πfC)

Answer

XC = 2πfC

Answer

XC = I/C

Answer

XC = C/I

Question 2

What is the condition for resonance in an AC circuit that contains an inductor and capacitor?

Accepted Answer

XL = XC

Answer

XL > XC

Answer

XL < XC

Answer

Z = 0

Question 3

Which device makes use of the principle of resonance?

Accepted Answer

Radio tuner

Answer

Electric motor

Answer

Transformer

Answer

Resistor

Question 4

In a series combination of an inductor and capacitor at resonance, what is the impedance?

Accepted Answer

Zero

Answer

Infinite

Answer

Equal to the resistance

Answer

Equal to the inductive reactance

Question 5

In an AC circuit, what type of opposition is offered to the flow of current by an inductor with inductance L?

Accepted Answer

Reactance

Answer

Resistance

Answer

Inductance

Answer

Capacitance

Question 6

In an AC circuit, a capacitor primarily stores energy in which form?

Accepted Answer

Electric field

Answer

Magnetic field

Answer

Gravitational field

Answer

Thermal energy

Question 7

As the frequency increases in an AC circuit, how does the impedance of a capacitor change?

Accepted Answer

Decreases

Answer

Increases

Answer

Remains the same

Answer

Becomes infinite

Question 8

Which of the following factors influence the resonant frequency of an LC circuit?

Accepted Answer

Inductance and capacitance

Answer

Resistance and inductance

Answer

Capacitance and resistance

Answer

Inductance, capacitance, and resistance

Question 9

In a series RLC circuit, what condition must be met for maximum power transfer to occur?

Accepted Answer

Inductive reactance = Capacitive reactance

Answer

Inductive reactance > Capacitive reactance

Answer

Capacitive reactance > Inductive reactance

Answer

Resistance = 0

Question 10

What is the function of a capacitor in a bypass filter?

Accepted Answer

To reduce noise

Answer

To block high-frequency signals

Answer

To pass high-frequency signals

Answer

To store charge

Question 11

Which instrument is used to measure inductance?

Accepted Answer

Inductance meter

Answer

Ammeter

Answer

Voltmeter

Answer

Ohmmeter

Question 12

A capacitor with a capacitance of 100 μF is connected to a sinusoidal voltage source with a frequency of 100 Hz and an amplitude of 10 V. What is the capacitive reactance of the capacitor?

Accepted Answer

10 Ω

Answer

1 Ω

Answer

100 Ω

Answer

1 kΩ

Question 13

In an AC circuit with a capacitor, the voltage across the capacitor:

Accepted Answer

Leads the current

Answer

Lags the current

Answer

Is in phase with the current

Answer

Is 90° out of phase with the current

Question 14

At resonance in a series RLC circuit, the impedance is:

Accepted Answer

Minimum

Answer

Maximum

Answer

Zero

Answer

Infinite

Question 15

The power factor of an AC circuit is defined as the:

Accepted Answer

Ratio of real power to apparent power

Answer

Ratio of apparent power to real power

Answer

Ratio of reactive power to real power

Answer

Ratio of real power to reactive power

Question 16

After a capacitor is disconnected from a DC voltage source, it:

Accepted Answer

Gradually discharges over time

Answer

Immediately discharges

Answer

Remains charged indefinitely

Answer

Charges in the opposite direction

Question 17

In an AC circuit, how does inductance affect its impedance?

Accepted Answer

Increases impedance

Answer

Reduces impedance

Question 18

In an AC circuit, an inductor with an inductance of 100 mH is connected in series with a capacitor. Calculate the capacitance required to achieve a resonant frequency of 1 kHz. Explain your reasoning.

Accepted Answer

100 μF

Answer

10 μF

Answer

1 mF

Answer

100 nF

Question 19

In an AC circuit, the current through an inductor lags the voltage across it by what phase angle?

Accepted Answer

90°

Answer

0°

Answer

180°

Answer

270°

Question 20

In an AC circuit, the current through a capacitor leads the voltage across it by what phase angle?

Accepted Answer

90°

Answer

0°

Answer

180°

Answer

270°

Question 21

The resonance frequency of an AC circuit containing an inductor and a capacitor in series is governed by which factors?

Accepted Answer

The inductance and capacitance of the circuit

Answer

The resistance and capacitance of the circuit

Answer

The inductance and resistance of the circuit

Answer

The capacitance and frequency of the AC source

Question 22

In an RLC circuit, what is the significance of the Quality Factor (Q-factor), and how does it relate to practical applications?

Accepted Answer

Describes the circuit's selectivity and energy dissipation.

Answer

Determines the circuit's phase shift and resonant frequency.

Answer

Relates the circuit's current and voltage amplitudes.

Question 23

In an AC circuit, which factors influence the impedance of a capacitor?

Accepted Answer

Frequency

Accepted Answer

Capacitance

Answer

Resistance

Answer

Voltage

Question 24

In an alternating current (AC) circuit, which component stores energy in the form of a magnetic field?

Accepted Answer

Inductor

Answer

Resistor

Answer

Capacitor

Question 25

In an AC circuit, which component stores energy in the form of an electric field?

Accepted Answer

Capacitor

Answer

Inductor

Answer

Resistor

Answer

Transistor

Question 26

The unit of capacitance in the International System of Units (SI) is:

Accepted Answer

Farad

Answer

Henry

Answer

Ohm

Answer

Siemens

Question 27

In an AC circuit, the combination of an inductor and a capacitor can result in:

Accepted Answer

Resonance

Answer

Oscillation

Answer

Amplification

Answer

Attenuation

Question 28

In an AC circuit containing both an inductor and a capacitor, the condition for resonance is given by:

Accepted Answer

XL = XC

Answer

ZL = 0

Answer

XL < XC

Answer

XL > XC

Question 29

In an AC circuit, the power dissipated by a capacitor is:

Accepted Answer

Zero

Answer

Negative

Answer

Positive

Question 30

In an AC circuit, the phase angle between the voltage and current is:

Accepted Answer

Determined by the circuit's impedance

Answer

Always zero

Answer

Always 90 degrees

Question 31

A capacitor in an AC circuit acts as a:

Accepted Answer

Storage element for electrical energy

Answer

Inductor of magnetic energy

Answer

Resistance to current flow

Answer

Conductor of electrical energy

Question 32

The capacitance of a capacitor depends on:

Accepted Answer

Plate area, distance between plates, and dielectric material

Answer

Current flowing through the capacitor

Answer

Voltage applied to the plates

Question 33

In a resonant AC circuit containing an inductor and a capacitor:

Accepted Answer

The inductive and capacitive reactances cancel each other out, resulting in maximum current flow

Answer

The current is at its minimum

Answer

The voltage is at its maximum

Question 34

In an AC circuit with both inductance and capacitance, the impedance is given by:

Accepted Answer

Z = √(R² + (XL - XC)²)

Answer

Z = 1 / (R + XL + XC)

Answer

Z = R * XL * XC

Answer

Z = R + XL - XC

Question 35

In an AC circuit, capacitors are known for their ability to store energy. Which of the following best describes how this energy is stored?

Accepted Answer

In the form of an electric field

Answer

In the form of a magnetic field

Answer

In the form of both electric and magnetic fields

Answer

Capacitors do not store energy

Question 36

Inductors, when used in AC circuits, exhibit a property known as impedance. How is the inductive impedance, XL, mathematically expressed?

Accepted Answer

XL = 2πfL

Answer

f = 2πXL

Answer

R = 2πfL

Answer

XC = 2πfL

Question 37

Consider a series LCR circuit. At resonance, a specific condition exists between the inductive impedance, XL, and the capacitive impedance, XC. What is this condition?

Accepted Answer

XL = XC

Answer

XL < XC

Answer

R = 0

Answer

XL > XC

Question 38

The power factor in an AC circuit is a crucial parameter. How is this factor mathematically defined?

Accepted Answer

Cos(θ)

Answer

Sin(θ)

Answer

Cot(θ)

Answer

Tan(θ)

Question 39

Capacitors, when used in AC circuits, exhibit a property known as reactance, denoted as XC. How is this capacitive reactance mathematically expressed?

Accepted Answer

XC = 1/(2πfC)

Answer

R = 1/(2πfC)

Answer

XL = 1/(2πfC)

Answer

C = 1/(2πfXL)

Question 40

Inductors find various applications in electrical engineering. Which of the following is NOT a typical application of inductors in this field?

Accepted Answer

Energy storage in batteries

Answer

Motors and generators

Answer

Filtering in power supplies

Answer

Coupling coils in transformers

Question 41

A 10 mH inductor is connected to a 120 V, 60 Hz AC source. Calculate the inductive reactance of the inductor.

Accepted Answer

37.7 Ω

Answer

113.1 Ω

Answer

18.8 Ω

Answer

77.7 Ω

Question 42

A series RLC circuit comprises a 100 Ω resistor, a 10 mH inductor, and a 10 μF capacitor. Calculate the circuit's resonant frequency.

Accepted Answer

1591.5 Hz

Answer

500 Hz

Answer

2000 Hz

Answer

100 Hz

Question 43

A 10 μF capacitor is connected to a 240 V, 50 Hz AC source. Calculate the capacitive reactance of the capacitor.

Accepted Answer

31.8 Ω

Answer

159.2 Ω

Answer

63.7 Ω

Answer

12.6 Ω

Question 44

In an AC circuit containing only an inductor, the current:

Accepted Answer

lags the voltage by 90 degrees.

Answer

leads the voltage by 90 degrees.

Answer

lags the voltage by 45 degrees.

Answer

leads the voltage by 45 degrees.

Question 45

In an AC circuit containing only a capacitor, the current:

Accepted Answer

leads the voltage by 90 degrees.

Answer

lags the voltage by 45 degrees.

Answer

lags the voltage by 90 degrees.

Answer

leads the voltage by 45 degrees.

Question 46

At resonance in a series RLC circuit, the impedance:

Accepted Answer

Is equal to the resistance (R).

Answer

Is equal to the inductive reactance (XL).

Answer

Is infinite.

Answer

Is zero.

Question 47

At resonance in an RLC circuit, the phase angle between the current and voltage is:

Accepted Answer

Zero.

Answer

45 degrees.

Answer

180 degrees.

Answer

90 degrees.

Question 48

Which of the following is NOT a typical application of capacitors in AC circuits?

Accepted Answer

Amplifying AC signals

Answer

Smoothing DC power supplies

Answer

Storing energy

Answer

Filtering AC signals

Question 49

Which of the following is NOT a typical application of inductors in AC circuits?

Accepted Answer

Regulating DC voltage

Answer

Creating magnetic fields

Answer

Storing energy

Answer

Filtering AC signals

Question 50

Calculate the resonant frequency of a circuit with an inductance of 1 mH and a capacitance of 1 μF.

Accepted Answer

159.2 kHz

Answer

318.5 kHz

Answer

637 kHz

Answer

79.6 kHz

Question 51

A capacitor of 10 μF is charged to 100 V. Determine the energy stored in the capacitor.

Accepted Answer

0.5 J

Answer

4 J

Answer

2 J

Answer

1 J