AC and DC Circuits: Master the Fundamentals of Electrical Circuits

Question 1

What law connects voltage, current, and resistance in a DC circuit?

Accepted Answer

Ohm's Law

Answer

Kirchhoff's Voltage Law

Answer

Faraday's Law

Answer

Lenz's Law

Question 2

In an AC circuit, which device is the primary source of voltage?

Accepted Answer

Generator

Answer

Battery

Answer

Solar cell

Answer

Transformer

Question 3

In a DC circuit, which statement accurately describes the direction of current flow?

Accepted Answer

It remains constant in one direction

Answer

It changes continuously

Answer

It reverses at regular intervals

Answer

It is not affected by the voltage input

Question 4

Which of the following units is used to measure electrical potential difference?

Accepted Answer

Volt

Answer

Ampere

Answer

Ohm

Answer

Watt

Question 5

The primary purpose of a fuse in an electrical circuit is to:

Accepted Answer

Protect the circuit from damage caused by excessive current

Answer

Regulate current flow

Answer

Store electrical energy

Answer

Improve circuit efficiency

Question 6

Which of the following is a fundamental property of a resistor?

Accepted Answer

It impedes the flow of current

Answer

It generates electrical energy

Answer

It stores electrical charge

Answer

It amplifies signals

Question 7

In a DC circuit, increasing the resistance will result in:

Accepted Answer

Decreased current flow

Answer

Increased current flow

Answer

No change in current flow

Answer

Reversed direction of current flow

Question 8

Which component is used to manually control the flow of current in a circuit?

Accepted Answer

Switch

Answer

Fuse

Answer

Resistor

Answer

Capacitor

Question 9

Which type of motor is commonly used in AC applications?

Accepted Answer

Induction motor

Answer

DC motor

Answer

Stepper motor

Answer

Synchronous motor

Question 10

The primary distinction between a transformer and an inductor is that:

Accepted Answer

A transformer transfers power, whereas an inductor stores energy

Answer

An inductor transfers power, whereas a transformer stores energy

Answer

Both transformers and inductors transfer power

Answer

Both transformers and inductors store energy

Question 11

Which of the following is NOT a characteristic of an AC circuit?

Accepted Answer

Power is constant.

Answer

Frequency is measured in Hertz.

Answer

Voltage and current do not have a constant phase difference.

Answer

Current flows in both directions.

Question 12

What is the difference between voltage and current?

Accepted Answer

Voltage is a measure of electrical potential, while current is a measure of the flow of electrical charge.

Answer

Voltage and current are the same thing.

Answer

Voltage is measured in volts, while current is measured in amps.

Answer

Voltage is a measure of electrical flow, while current is a measure of electrical potential.

Question 13

Which type of circuit has only one path for current to flow?

Accepted Answer

Series circuit

Answer

Parallel circuit

Answer

Open circuit

Answer

Combination circuit

Question 14

What is the formula for calculating the total resistance of a series circuit?

Accepted Answer

Total Resistance is the sum of the individual resistances (R = R1 + R2 + ... + Rn)

Answer

Total Resistance is the difference of the individual resistances (R = R1 - R2 - ... - Rn)

Answer

Total Resistance is the product of the individual resistances (R = R1 x R2 x ... x Rn)

Answer

Total Resistance is the quotient of the individual resistances (R = R1 / R2 / ... / Rn)

Question 15

What is the formula for calculating the total resistance of a parallel circuit?

Accepted Answer

The reciprocal of the total resistance is equal to the sum of the reciprocals of the individual resistances (1/R = 1/R1 + 1/R2 + ... + 1/Rn)

Answer

Total Resistance is the difference of the individual resistances (R = R1 - R2 - ... - Rn)

Answer

Total Resistance is the sum of the individual resistances (R = R1 + R2 + ... + Rn)

Answer

Total Resistance is the product of the individual resistances (R = R1 x R2 x ... x Rn)

Question 16

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

Accepted Answer

To protect the circuit from damage caused by excessive current.

Answer

To store electrical energy.

Answer

To provide a path for current to flow.

Answer

To regulate the voltage in the circuit.

Question 17

Which type of electrical wire is typically used for residential wiring?

Accepted Answer

Romex

Answer

Fiber optic cable

Answer

Cat5e cable

Answer

Coaxial cable

Question 18

What is the difference between a conductor and an insulator?

Accepted Answer

Conductors allow electric current to flow easily, while insulators do not.

Answer

Insulators allow electric current to flow easily, while conductors do not.

Answer

Conductors and insulators are the same thing.

Answer

Conductors are measured in ohms, while insulators are measured in volts.

Question 19

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

Accepted Answer

AC circuits have varying voltage and current, while DC circuits have constant voltage and current.

Answer

AC circuits use higher voltages than DC circuits.

Answer

AC circuits are more dangerous than DC circuits.

Answer

DC circuits are more efficient than AC circuits.

Question 20

What is the frequency of an AC circuit that completes 50 cycles in one second?

Accepted Answer

50 Hz

Answer

100 Hz

Answer

200 Hz

Answer

25 Hz

Question 21

What is the relationship between voltage (V), current (I), and resistance (R) in a DC circuit?

Accepted Answer

V = IR

Answer

I = V/R

Answer

V = I/R

Answer

R = V/I

Question 22

Which of the following devices is commonly used to convert DC to AC?

Accepted Answer

Inverter

Answer

Transformer

Answer

Rectifier

Answer

Capacitor

Question 23

Which of the following factors does NOT affect the inductance of a coil?

Accepted Answer

Voltage

Answer

Coil length

Answer

Core material

Answer

Number of turns

Question 24

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

Accepted Answer

To store and release electrical energy, causing a phase shift.

Answer

To reduce voltage

Answer

To increase current flow

Answer

To block AC current

Question 25

What is a primary advantage of using AC circuits for power transmission over long distances?

Accepted Answer

AC voltage can be easily stepped up using transformers, reducing power loss due to resistance.

Answer

AC circuits are less expensive to install.

Answer

AC circuits can transmit power over greater distances without signal distortion.

Answer

AC current is safer than DC current.

Question 26

Which of the following is a fundamental characteristic of a DC circuit?

Accepted Answer

Electrons flow in one direction only.

Answer

Current changes direction at regular intervals.

Answer

Voltage fluctuates periodically.

Answer

Frequency determines how often the current reverses.

Question 27

In an AC circuit, what does 'peak-to-peak voltage' refer to?

Accepted Answer

Maximum voltage difference between the positive and negative peaks.

Answer

Frequency of the voltage waveform.

Answer

Average voltage level over time.

Answer

Time taken for one complete cycle.

Question 28

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

Accepted Answer

Material, length, and cross-sectional area.

Answer

Voltage and current flowing through the conductor.

Answer

Temperature and humidity of the environment.

Answer

Frequency and wavelength of the current.

Question 29

What is the term used to describe the total opposition to current flow in an AC circuit?

Accepted Answer

Impedance

Answer

Capacitance

Answer

Resistance

Answer

Reactance

Question 30

Which of the following precisely describes a characteristic of an alternating current (AC) circuit?

Accepted Answer

Current continually reverses direction and changes magnitude over time.

Answer

Voltage remains constant and unchanging over time.

Answer

Current flows consistently in only one direction.

Question 31

In a Direct Current (DC) circuit, which formula accurately calculates the current?

Accepted Answer

I = V / R

Answer

I = V ^ R

Answer

I = V * R

Answer

I = R / V

Question 32

Which type of resistor is specifically designed to regulate and control the flow of current within a circuit?

Accepted Answer

Variable resistor

Answer

Fixed resistor

Answer

Capacitor

Answer

Inductor

Question 33

When handling AC circuits, which safety precaution is crucial to adhere to?

Accepted Answer

Utilize insulated tools and wear protective rubber gloves.

Answer

Make direct contact with live wires using bare hands.

Answer

Ignore established safety warnings and procedures.

Answer

Work in environments with moisture or dampness.

Question 34

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

Accepted Answer

To store and subsequently release electrical energy.

Answer

To increase the circuit's voltage.

Answer

To obstruct the flow of alternating current.

Answer

To diminish the power factor.

Question 35

How does the Root Mean Square (RMS) value of an AC voltage compare to its peak value?

Accepted Answer

The RMS value is consistently lower than the peak value by a factor of square root of 2.

Answer

The RMS value is consistently higher than the peak value by a factor of square root of 2.

Answer

The RMS value is always equal to the peak value.

Question 36

In power transmission, what advantage does AC offer over DC?

Accepted Answer

Reduced power loss over extended distances due to the mitigation of the skin effect.

Answer

Increased efficiency in converting mechanical energy into electrical energy.

Answer

Ability to power devices that require both AC and DC inputs.

Question 37

Which formula accurately calculates the frequency of an AC circuit?

Accepted Answer

f = 1 / T

Answer

f = 1 / T^2

Answer

f = T / 1

Answer

f = T * 1

Question 38

Which device serves the purpose of converting AC voltage to DC voltage?

Accepted Answer

Rectifier

Answer

Capacitor

Answer

Inductor

Answer

Transformer

Question 39

Which of the following describes a fundamental characteristic of Alternating Current (AC) circuits?

Accepted Answer

Voltage and current periodically change direction

Answer

Voltage and current maintain constant values

Answer

Resistance is the exclusive factor influencing current flow

Answer

Current flows solely in a single direction

Question 40

In a Direct Current (DC) circuit, current behaves in which manner?

Accepted Answer

Flows consistently in one direction only

Answer

Flows exclusively when voltage is elevated

Answer

Flows solely when resistance is minimal

Answer

Periodically alternates its direction

Question 41

Within an electrical circuit, which component primarily impedes the flow of current?

Accepted Answer

Resistor

Answer

Diode

Answer

Inductor

Answer

Capacitor

Question 42

Which unit of measurement is employed to quantify electrical current?

Accepted Answer

Ampere (A)

Answer

Volt (V)

Answer

Farad (F)

Answer

Ohm (Ω)

Question 43

In a parallel circuit configuration, the current:

Accepted Answer

Divides among the component branches

Answer

Is directly proportionate to the applied voltage

Answer

Remains identical across all branches

Answer

Is inversely proportionate to the total resistance

Question 44

The formula for calculating power dissipation in a resistor is:

Accepted Answer

P = I^2 * R

Answer

P = I * V

Answer

P = V^2 / R

Answer

P = V / R

Question 45

Which of the following best describes a key characteristic of an alternating current (AC) circuit?

Accepted Answer

Voltage and current reverse direction periodically

Answer

Voltage and current are constant

Answer

Voltage and current are perfectly in phase

Answer

Current flows only in one direction

Question 46

What is the correct formula for calculating the resistance of a resistor?

Accepted Answer

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

Answer

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

Answer

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

Answer

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

Question 47

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

Accepted Answer

To protect the circuit from overcurrent

Answer

To store electrical energy

Answer

To regulate voltage

Answer

To control the flow of current

Question 48

What is the fundamental difference between a series circuit and a parallel circuit?

Accepted Answer

In a series circuit, components are connected end-to-end, while in a parallel circuit, components are connected side-by-side

Answer

Series circuits have higher resistance than parallel circuits

Question 49

Which of the following is the unit of electrical power?

Accepted Answer

Watt

Answer

Ohm

Answer

Ampere

Question 50

What is the formula to calculate the power dissipated by a resistor?

Accepted Answer

Power (P) = Current (I) squared x Resistance (R)

Answer

Power (P) = Resistance (R) / Current (I)

Answer

Power (P) = Voltage (V) x Current (I)

Question 51

What is the primary purpose of an inductor in an electrical circuit?

Accepted Answer

To store energy in a magnetic field

Answer

To increase voltage

Answer

To block DC current

Answer

To decrease current