Electrical Theory Review: Master the Fundamentals of Electricity

Question 1

Which of the following is a unit of electrical power?

Accepted Answer

Watt

Answer

Ohm

Answer

Ampere

Answer

Volt

Question 2

A voltage source with a higher voltage will cause:

Accepted Answer

More current to flow through a resistor

Answer

Less current to flow through a resistor

Answer

A higher resistance in the circuit

Answer

A lower resistance in the circuit

Question 3

Which of the following is NOT a basic electrical quantity?

Accepted Answer

Energy

Answer

Voltage

Answer

Current

Answer

Power

Question 4

A circuit with multiple resistors connected in parallel will have:

Accepted Answer

Lower total resistance than any individual resistor

Answer

Higher total resistance than any individual resistor

Answer

Equal total resistance to any individual resistor

Answer

Zero total resistance

Question 5

Which of the following is a property of an ideal voltage source?

Accepted Answer

Zero internal resistance

Answer

Infinite internal resistance

Answer

High internal resistance

Answer

Low internal resistance

Question 6

A capacitor stores electrical energy in the form of:

Accepted Answer

Electric field

Answer

Magnetic field

Answer

Chemical energy

Answer

Mechanical energy

Question 7

Which of the following is a tool used to measure electrical current?

Accepted Answer

Ammeter

Answer

Voltmeter

Answer

Ohmmeter

Answer

Wattmeter

Question 8

A short circuit occurs when:

Accepted Answer

The resistance of the circuit is very low

Answer

The resistance of the circuit is very high

Answer

The voltage of the circuit is very high

Answer

The current of the circuit is very low

Question 9

Which of the following is a characteristic of an insulator?

Accepted Answer

Low electrical conductivity

Answer

High electrical conductivity

Answer

High thermal conductivity

Answer

Low thermal conductivity

Question 10

Which of the following is the SI unit of voltage?

Accepted Answer

Volt (V)

Answer

Watt (W)

Answer

Ohm (Ω)

Answer

Ampere (A)

Question 11

The flow of electric charge in a circuit is called:

Accepted Answer

Current (I)

Answer

Power (P)

Answer

Resistance (R)

Answer

Voltage (V)

Question 12

The opposition to the flow of electric current in a circuit is called:

Accepted Answer

Resistance (R)

Answer

Current (I)

Answer

Power (P)

Answer

Voltage (V)

Question 13

The rate at which electrical energy is transferred or consumed is called:

Accepted Answer

Power (P)

Answer

Current (I)

Answer

Voltage (V)

Question 14

In a series circuit, the total resistance is:

Accepted Answer

The sum of individual resistances

Answer

The difference between individual resistances

Answer

The average of individual resistances

Answer

The product of individual resistances

Question 15

In a parallel circuit, the total current is:

Accepted Answer

The sum of individual currents

Answer

The difference between individual currents

Answer

The average of individual currents

Answer

The product of individual currents

Question 16

Which of the following materials is a good conductor of electricity?

Accepted Answer

Copper

Answer

Rubber

Answer

Wood

Answer

Plastic

Question 17

Which of the following materials is a semiconductor?

Accepted Answer

Silicon

Answer

Plastic

Answer

Rubber

Answer

Copper

Question 18

Which of the following is a common source of voltage?

Accepted Answer

Battery

Answer

Inductor

Answer

Resistor

Answer

Capacitor

Question 19

In a series circuit, which equation correctly describes the relationship between voltage (V), current (I), and resistance (R)?

Accepted Answer

V = I * R

Answer

V = I + R

Answer

V = I - R

Question 20

Which of the following units measures the electrical potential difference, commonly known as voltage?

Accepted Answer

Volt

Answer

Ohm

Answer

Watt

Answer

Ampere

Question 21

In an electrical circuit, which formula accurately describes the calculation of current?

Accepted Answer

Current = Voltage / Resistance

Answer

Current = Power / Voltage

Answer

Current = Resistance / Voltage

Answer

Current = Power / Resistance

Question 22

In the field of electrical circuits, what is the SI unit used to measure power?

Accepted Answer

Watt

Answer

Volt

Answer

Ampere

Answer

Ohm

Question 23

When classifying materials based on their electrical properties, which of the following is considered a good conductor of electricity?

Accepted Answer

Copper

Answer

Wood

Answer

Rubber

Answer

Plastic

Question 24

In an electrical circuit, what is the primary function of a resistor?

Accepted Answer

To regulate and control the flow of current

Answer

To store electrical energy

Answer

To amplify voltage

Answer

To operate as an electrical switch

Question 25

In a resistive circuit, describe the relationship between voltage and current. How are they linked?

Accepted Answer

Directly proportional

Answer

Not related

Answer

Exponentially proportional

Answer

Inversely proportional

Question 26

What is the fundamental SI unit for measuring electrical current?

Accepted Answer

Ampere (A)

Answer

Volt (V)

Answer

Watt (W)

Answer

Ohm (Ω)

Question 27

What physical quantity refers to the difference in electrical potential between two points?

Accepted Answer

Voltage (V)

Answer

Power (W)

Answer

Current (A)

Answer

Resistance (Ω)

Question 28

Which material exhibits low electrical resistance, allowing it to effectively conduct electricity?

Accepted Answer

Copper (Cu)

Answer

Rubber

Answer

Wood

Answer

Plastic

Question 29

Ohm's Law mathematically relates which three fundamental electrical quantities?

Accepted Answer

Voltage (V), Current (A), and Resistance (Ω)

Answer

Capacitance (F), Inductance (H), and Resistance (Ω)

Answer

Frequency (Hz), Wavelength (m), and Amplitude

Answer

Energy (J), Power (W), and Time (s)

Question 30

Which type of resistor can have its resistance value adjusted?

Accepted Answer

Variable resistor

Answer

Metal film resistor

Answer

Ceramic resistor

Answer

Carbon resistor

Question 31

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

Accepted Answer

To store electrical energy

Answer

To block alternating current

Answer

To dissipate electrical power

Answer

To conduct direct current

Question 32

Which unit is used to express the rate of electrical energy transfer or consumption?

Accepted Answer

Watt (W)

Answer

Volt (V)

Answer

Ampere (A)

Answer

Ohm (Ω)

Question 33

Which safety precaution is crucial to follow when working with electrical circuits?

Accepted Answer

Always disconnect the power source before initiating any work

Answer

Wear insulated gloves only

Answer

Work in a well-lit area

Answer

Use a multimeter to check for voltage

Question 34

Which measuring instrument is specifically designed to measure electrical current?

Accepted Answer

Ammeter

Answer

Voltmeter

Answer

Ohmmeter

Question 35

In a series electrical circuit, how is the total resistance calculated?

Accepted Answer

By adding the individual resistances of all components

Answer

By taking the average of the individual resistances

Answer

By multiplying the individual resistances

Question 36

Which of the following is the SI unit of measurement for electrical current?

Accepted Answer

Amperes (A)

Answer

Ohms (Ω)

Answer

Volts (V)

Answer

Coulombs (C)

Question 37

In a simple electrical circuit, what is the relationship between voltage (V), current (I), and resistance (R)?

Accepted Answer

Ohm's Law: Voltage = Current × Resistance (V = IR)

Answer

Kirchhoff's Voltage Law: Voltage = Current + Resistance (V = I + R)

Answer

Resistance Law: Current = Voltage × Resistance (I = V × R)

Answer

Power Law: Voltage = Current ÷ Resistance (V = I ÷ R)

Question 38

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

Accepted Answer

To store electrical energy in an electric field

Answer

To conduct electricity unidirectionally

Answer

To protect against overcurrent

Answer

To generate electricity from mechanical energy

Question 39

Which type of electrical circuit provides multiple paths for current to flow?

Accepted Answer

Parallel circuit

Answer

Open circuit

Answer

Series circuit

Answer

Closed circuit

Question 40

What is the main purpose of a transformer in an electrical system?

Accepted Answer

To change the voltage level of alternating current (AC)

Answer

To store electrical energy

Answer

To increase the current flow

Answer

To protect against overloads

Question 41

Which of the following is a crucial electrical safety precaution that should NOT be followed?

Accepted Answer

Working on live electrical equipment without proper safety measures

Answer

Wearing appropriate personal protective equipment (PPE)

Answer

Inspecting electrical equipment for damage before use

Answer

Using insulated tools and equipment

Question 42

What type of electrical device converts alternating current (AC) to direct current (DC)?

Accepted Answer

Rectifier

Answer

Resistor

Answer

Transformer

Answer

Capacitor

Question 43

What is the relationship between electrical power (P), voltage (V), and current (I)?

Accepted Answer

Power = Voltage × Current (P = VI)

Answer

Current = Power ÷ Voltage (I = P ÷ V)

Answer

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

Answer

Voltage = Power ÷ Current (V = P ÷ I)

Question 44

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

Accepted Answer

To protect the circuit from damage caused by overcurrent

Answer

To store electrical energy

Answer

To connect different components

Answer

To regulate voltage levels

Question 45

Which of the following is the international standard (SI) unit for electric current?

Accepted Answer

Ampere (A)

Answer

Ohm (Ω)

Answer

Volt (V)

Answer

Watt (W)

Question 46

Which of the following materials is an excellent conductor of electricity?

Accepted Answer

Copper

Answer

Rubber

Answer

Glass

Answer

Wood

Question 47

State the formula for calculating electrical power in a circuit.

Accepted Answer

Power = Voltage × Current (P = V × I)

Answer

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

Answer

Power = Resistance × Voltage (P = R × V)

Answer

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

Question 48

Which of the following is a primary source of electrical energy?

Accepted Answer

Battery

Answer

Resistor

Answer

Capacitor

Answer

Light bulb

Question 49

Describe the key difference between AC and DC current.

Accepted Answer

AC current periodically changes direction, while DC current flows in only one direction.

Answer

DC current is more efficient than AC current.

Answer

AC current has a higher voltage than DC current.

Question 50

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

Accepted Answer

To protect the circuit from excessive current (overcurrent).

Answer

To control the flow of current in the circuit.

Answer

To convert AC current to DC current.

Answer

To store electrical energy.

Question 51

Which of the following is a crucial safety precaution when working with electricity?

Accepted Answer

Always wear insulated gloves and safety glasses.

Answer

Use metal tools to test for electricity.

Answer

Work on live circuits whenever possible.

Answer

Ignore safety precautions and prioritize task completion.

Question 52

What is the primary function of a transformer in an electrical system?

Accepted Answer

To alter the voltage or current levels in a circuit.

Answer

To store electrical energy.

Answer

To protect the circuit from overcurrent.

Question 53

Which of the following is considered a renewable source of electrical energy?

Accepted Answer

Solar power

Answer

Coal-fired power plant

Answer

Nuclear power plant

Answer

Natural gas power plant