AC and DC Circuits: Master the Fundamentals of Electrical Circuits

Question 1

Rephrased: Which of the following applications commonly employs AC circuits?

Accepted Answer

Simplified: Power transmission

Answer

Corrected: Battery charging

Answer

Rewritten: Electroplating

Answer

Revised: Transistor biasing

Question 2

Revised: Which device is appropriate for measuring AC voltage?

Accepted Answer

Simplified: Voltmeter

Answer

Removed: Ammeter

Answer

Removed: Ohmmeter

Answer

Removed: Capacitance meter

Question 3

Revised: What is the primary purpose of a transformer in an AC circuit?

Accepted Answer

Simplified: Voltage level conversion

Answer

Removed: Circuit isolation

Answer

Removed: AC-to-DC conversion

Answer

Removed: Energy storage

Question 4

Which circuit component exhibits resistance to the flow of electrical current?

Accepted Answer

Resistor

Answer

Capacitor

Answer

Inductor

Answer

Transformer

Question 5

State the primary function of a diode in a circuit:

Accepted Answer

To permit current flow in a single direction

Answer

To store electrical energy

Answer

To amplify voltage

Answer

To reduce resistance

Question 6

What is the main purpose of a transformer in an AC circuit?

Accepted Answer

To alter voltage levels

Answer

To change AC voltage frequency

Answer

To convert AC voltage to DC voltage

Answer

To store electrical energy

Question 7

In real-world applications, why is AC preferred for power transmission over long distances, while DC is preferred for flashlights?

Accepted Answer

AC: power transmission over long distances; DC: flashlights

Answer

AC: batteries; DC: power plants

Answer

AC: computers; DC: televisions

Answer

AC: solar panels; DC: generators

Question 8

Which statement accurately describes the direction of current flow in an AC circuit?

Accepted Answer

Current reverses direction periodically.

Answer

Current flows in one direction at all times.

Answer

Current fluctuates randomly.

Answer

Current direction is determined by the voltage source.

Question 9

Which advantage is associated with DC motors?

Accepted Answer

High starting torque

Answer

Low maintenance

Answer

Variable speed control

Answer

Compact size

Question 10

In an AC circuit, what is the primary function of a capacitor?

Accepted Answer

Storing electrical energy

Answer

Blocking DC current

Answer

Reducing voltage

Answer

Increasing power factor

Question 11

Which is a common application of a DC circuit?

Accepted Answer

Operating electronic devices

Answer

Powering vehicles

Answer

Transmitting data

Answer

Generating electricity

Question 12

Which of the following is not a type of AC generator?

Accepted Answer

DC generator

Answer

Synchronous generator

Answer

Induction generator

Answer

Permanent magnet generator

Question 13

What is the key difference between a conductor and an insulator?

Accepted Answer

Conductors allow current to flow freely, while insulators resist current flow.

Answer

Insulators allow current to flow freely, while conductors resist current flow.

Answer

Conductors are typically made of plastic, while insulators are typically made of metal.

Answer

Insulators are typically made of plastic, while conductors are typically made of metal.

Question 14

Which mathematical equation correctly expresses Ohm's law, describing the relationship between voltage (V), current (I), and resistance (R)?

Accepted Answer

I = V / R

Answer

V = I + R

Answer

R = V - I

Answer

V = I * R^2

Question 15

In an AC circuit, which of the following characteristics is observed?

Accepted Answer

Current and voltage change direction periodically

Answer

Current and voltage remain constant

Answer

Current flows in a single direction

Answer

Voltage is measured in volts

Question 16

What formula is used to calculate the resistance (R) of a resistor?

Accepted Answer

R = V/I

Answer

R = I/V

Answer

R = V*I

Answer

R = I*V

Question 17

What is the primary purpose of a fuse in an electrical circuit?

Accepted Answer

To protect the circuit from excessive current

Answer

To regulate voltage

Answer

To store energy

Answer

To convert AC to DC

Question 18

Which unit is commonly used to measure electrical power?

Accepted Answer

Watts

Answer

Volts

Answer

Amperes

Answer

Ohms

Question 19

What is the main function of a transformer in an electrical circuit?

Accepted Answer

To change the voltage level

Answer

To control the current flow

Answer

To store energy

Answer

To protect the circuit from short circuits

Question 20

In a DC circuit, the current flows in which direction?

Accepted Answer

One direction only

Answer

Both directions

Answer

Randomly

Answer

It depends on the voltage

Question 21

In troubleshooting an AC electrical circuit, which component should be checked first?

Accepted Answer

Fuse

Answer

Capacitor

Answer

Inductor

Answer

Resistor

Question 22

Which of the following is a key difference between AC and DC circuits?

Accepted Answer

AC circuits have alternating current, while DC circuits have direct current.

Accepted Answer

AC circuits can transmit power over long distances without significant power loss, while DC circuits cannot.

Answer

DC circuits are more efficient than AC circuits.

Answer

AC circuits use square waves, while DC circuits use sine waves.

Question 23

Which of the following is a fundamental difference between AC (Alternating Current) and DC (Direct Current) circuits?

Accepted Answer

AC periodically changes direction while DC flows consistently in one direction

Answer

AC has a higher voltage and DC has a lower voltage

Answer

AC operates at a higher frequency, while DC operates at a lower frequency

Question 24

What is the primary application of AC circuits?

Accepted Answer

Transmission of electrical power over long distances

Answer

Battery charging

Answer

Automotive electrical systems

Answer

Powering electronic devices

Question 25

Which of the following components is used to store electrical energy in DC circuits?

Accepted Answer

Capacitor

Answer

Resistor

Answer

Inductor

Answer

Transformer

Question 26

What is the formula for calculating the resistance of a conductor?

Accepted Answer

R (Resistance) = V (Voltage) / I (Current)

Answer

R = I / V

Answer

R = V / P (Power)

Answer

R = P / I

Question 27

Which of the following factors affects the inductance of a coil?

Accepted Answer

Number of turns in the coil

Answer

Cross-sectional area of the coil

Answer

Voltage applied to the coil

Answer

Resistance of the coil

Question 28

What is the function of a transformer in an AC circuit?

Accepted Answer

To change voltage and current levels while maintaining power

Answer

To convert AC to DC

Answer

To store electrical energy

Answer

To filter noise from the circuit

Question 29

What is the effect of resistance in an AC circuit?

Accepted Answer

Reduces current flow and causes a voltage drop across the resistor

Answer

Increases current flow and causes a voltage rise across the resistor

Answer

Has no effect on current or voltage

Answer

Converts AC to DC

Question 30

Which of the following is a potential hazard associated with AC circuits?

Accepted Answer

Electrocution

Answer

Explosion

Answer

Radiation

Question 31

What is the main purpose of using a multimeter in AC and DC circuits?

Accepted Answer

To measure voltage, current, and resistance

Answer

To generate AC and DC signals

Answer

To convert AC to DC

Answer

To amplify signals

Question 32

What is a fundamental difference between AC and DC circuits?

Accepted Answer

In AC circuits, the current periodically reverses direction, while in DC circuits, the current flows in only one direction.

Answer

DC circuits have higher efficiency than AC circuits.

Answer

AC circuits operate on higher voltages compared to DC circuits.

Question 33

In an AC circuit, how are voltage and current related?

Accepted Answer

Voltage and current oscillate in step, both crossing zero simultaneously.

Answer

Voltage and current are consistently 90 degrees out of phase.

Answer

Voltage and current are always in phase.

Question 34

What is the function of a capacitor in an AC circuit?

Accepted Answer

To store and release electrical energy, shifting the phase angle.

Answer

To block DC current

Answer

To boost voltage

Question 35

What formula calculates the impedance of an AC circuit?

Accepted Answer

Impedance = √(Resistance^2 + (Inductive Reactance - Capacitive Reactance)^2)

Answer

Impedance = Resistance / (Inductive Reactance - Capacitive Reactance)

Answer

Impedance = Resistance + (Inductive Reactance - Capacitive Reactance)

Question 36

What primary safety risk is associated with AC circuits?

Accepted Answer

Electrical shock

Answer

Fire

Answer

Radiation exposure

Answer

Chemical burns

Question 37

What is an example of a DC circuit application?

Accepted Answer

Battery-powered devices

Answer

Lighting

Answer

Industrial machinery

Answer

Power transmission

Question 38

What is the main distinction between a series circuit and a parallel circuit?

Accepted Answer

In a series circuit, the current remains constant throughout, whereas in a parallel circuit, the voltage remains constant across all branches.

Answer

Series circuits offer higher efficiency than parallel circuits.

Question 39

Which of the following is a characteristic of AC circuits?

Accepted Answer

Voltage and current change direction periodically

Answer

Power is constant throughout the circuit

Answer

Voltage remains constant

Answer

Current flows in a single direction

Question 40

In a DC circuit, the current:

Accepted Answer

Flows continuously in one direction

Answer

Changes direction periodically

Answer

Alternates its direction periodically

Answer

Can be either AC or DC

Question 41

The unit of measurement for the frequency of an AC circuit is:

Accepted Answer

Hertz (Hz)

Answer

Volts (V)

Answer

Watts (W)

Answer

Amperes (A)

Question 42

Which of the following factors can influence the resistance of a conductor?

Accepted Answer

Length, cross-sectional area, and material composition

Answer

Capacitance and inductance

Answer

Frequency and power factor

Answer

Voltage and current

Question 43

In an inductive circuit, the current:

Accepted Answer

Lags behind the voltage

Answer

Is in phase with the voltage

Answer

Leads the voltage

Answer

Remains constant

Question 44

The power factor of a circuit is:

Accepted Answer

The ratio of real power to apparent power

Answer

The angle between voltage and current

Answer

The ratio of voltage to current

Answer

The frequency of the circuit

Question 45

Which of the following is a crucial safety measure when working with AC circuits?

Accepted Answer

Using insulated tools and wearing appropriate protective gear

Answer

Working on live circuits

Answer

Ignoring warning labels

Answer

Touching bare wires

Question 46

A key difference between AC and DC circuits is that:

Accepted Answer

AC periodically reverses its direction, while DC flows in one direction only.

Answer

DC circuits have less resistance than AC circuits.

Answer

AC has a higher current than DC.

Question 47

In an AC circuit, the voltage and current:

Accepted Answer

Vary sinusoidally, reaching their maximum and minimum values at different times.

Answer

Are always 180 degrees out of phase.

Answer

Are always synchronized with each other.

Question 48

Which component within an AC circuit stores energy in the form of a rotating magnetic field?

Accepted Answer

Inductor

Answer

Capacitor

Answer

Diode

Answer

Resistor

Question 49

The power factor in an AC circuit is represented as:

Accepted Answer

The ratio of real power to apparent power.

Answer

The sum of real power and apparent power.

Answer

The difference between real power and apparent power.

Answer

The ratio of apparent power to real power.

Question 50

Which circuit type utilizes a battery as its power source?

Accepted Answer

DC circuit

Answer

Three-phase circuit

Answer

AC circuit

Answer

Resonant circuit

Question 51

The peak-to-peak voltage of an AC waveform is:

Accepted Answer

The difference between the maximum and minimum voltage values.

Answer

The average voltage value.

Answer

The root mean square voltage value.

Question 52

Within a DC circuit, the current is:

Accepted Answer

Constant and unidirectional.

Answer

Alternating and bidirectional.

Answer

Square wave and bidirectional.

Answer

Sinusoidal and unidirectional.

Question 53

In a DC circuit, which component provides a path for current flow?

Accepted Answer

Conductor

Answer

Transformer

Answer

Insulator

Answer

Semiconductor