# Top Electrical Engineering Multiple Choice Questions and Answers (MCQ)

## What is the SI unit of electrical resistance?

a. Ampere
b. Ohm
c. Volt
d. Watt

Ohm is the SI unit of electrical resistance.

## What is the difference between AC and DC?

a. AC stands for alternative current, while DC stands for direct current
b. AC is more dangerous than DC
c. AC is used for low voltage applications, while DC is used for high voltage applications
d. There is no difference between AC and DC

AC stands for alternative current, while DC stands for direct current.

## What is an electrical circuit?

a. A device that generates electricity
b. A device that stores electricity
c. A path along which electric current can flow
d. A device that measures electricity

An electrical circuit is a path along which electric current can flow.

## What is the purpose of a transformer?

a. To convert AC to DC
b. To convert DC to AC
c. To increase or decrease voltage levels
d. To store electrical energy

The purpose of a transformer is to increase or decrease voltage levels.

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

a. Conductors allow electric current to flow through them, while insulators do not
b. Conductors are used in high voltage applications, while insulators are used in low voltage applications
c. Insulators are made of metal, while conductors are made of non-metal materials
d. There is no difference between a conductor and an insulator

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

## What is an electric motor?

a. A device that converts mechanical energy into electrical energy
b. A device that converts electrical energy into mechanical energy
c. A device that stores electrical energy
d. A device that measures electrical energy

An electric motor is a device that converts electrical energy into mechanical energy.

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

a. In a series circuit, the components are connected one after the other, while in a parallel circuit, the components are connected side by side
b. In a series circuit, the voltage is divided among the components, while in a parallel circuit, the voltage is the same across all components
c. Series circuits are used for high voltage applications, while parallel circuits are used for low voltage applications
d. There is no difference between a series and a parallel circuit

In a series circuit, the components are connected one after the other, while in a parallel circuit, the components are connected side by side.

## What is an electrical fuse?

a. A device that converts electrical energy into mechanical energy
b. A device that stores electrical energy
c. A device that measures electrical energy
d. A device that protects electrical circuits from overcurrent

An electrical fuse is a device that protects electrical circuits from overcurrent.

## What is an electric generator?

a. A device that converts mechanical energy into electrical energy
b. A device that converts electrical energy into mechanical energy
c. A device that stores electrical energy
d. A device that measures electrical energy

An electric generator is a device that converts mechanical energy into electrical energy.

## What is an electrical relay?

a. A device that converts electrical energy into mechanical energy
b. A device that stores electrical energy
c. A device that measures electrical energy
d. A device that controls the flow of electrical current

## What is an electrical circuit breaker?

a. A device that converts electrical energy into mechanical energy
b. A device that stores electrical energy
c. A device that measures electrical energy
d. A device that interrupts electrical current when it exceeds a safe level

An electrical circuit breaker is a device that interrupts electrical current when it exceeds a safe level.

## What is the difference between a capacitor and a battery?

a. Capacitors store energy in an electric field, while batteries store energy in a chemical form
b. Capacitors are used in low voltage applications, while batteries are used in high voltage applications
c. Capacitors can store more energy than batteries
d. There is no difference between a capacitor and a battery

Capacitors store energy in an electric field, while batteries store energy in a chemical form.

## What is an electrical inductor?

a. A device that converts electrical energy into mechanical energy
b. A device that stores electrical energy
c. A device that measures electrical energy
d. A device that opposes changes in electrical current

An electrical inductor is a device that opposes changes in electrical current.

## What is the purpose of a diode?

a. To convert AC to DC
b. To convert DC to AC
c. To regulate voltage levels
d. To allow current to flow in only one direction

The purpose of a diode is to allow current to flow in only one direction.

## What is electrical resistance?

a. The ability of a material to conduct electricity
b. The ability of a material to store electricity
c. The ability of a material to oppose the flow of electricity
d. The ability of a material to measure electricity

Electrical resistance is the ability of a material to oppose the flow of electricity.

## What is an electrical load?

a. A device that generates electricity
b. A device that stores electricity
c. A device that measures electricity
d. A device that consumes electrical energy

An electrical load is a device that consumes electrical energy.

## What is an electrical insulator?

a. A material that allows electricity to flow through it
b. A material that stores electrical energy
c. A material that opposes the flow of electricity
d. A material that measures electricity

An electrical insulator is a material that opposes the flow of electricity.

## What is an electrical conductor?

a. A material that allows electricity to flow through it
b. A material that stores electrical energy
c. A material that opposes the flow of electricity
d. A material that measures electricity

An electrical conductor is a material that allows electricity to flow through it.

## What is the difference between an open circuit and a short circuit?

a. An open circuit is a circuit that is incomplete, while a short circuit is a circuit with low resistance
b. An open circuit is a circuit with low resistance, while a short circuit is a circuit that is incomplete
c. There is no difference between an open circuit and a short circuit
d. An open circuit and a short circuit are the same things

An open circuit is a circuit that is incomplete, while a short circuit is a circuit with low resistance.

## What is an electrical transducer?

a. A device that converts electrical energy into mechanical energy
b. A device that converts mechanical energy into electrical energy
c. A device that measures electrical energy
d. A device that converts one form of energy into another form

## What is the purpose of a transformer in an electrical circuit?

a. To convert AC to DC
b. To convert DC to AC
c. To increase or decrease voltage levels
d. To regulate current levels

The purpose of a transformer in an electrical circuit is to increase or decrease voltage levels.

## What is an electrical ground?

a. A source of electrical power
b. A device that measures electrical energy
c. A point of zero electrical potential
d. A device that stores electrical energy

An electrical ground is a point of zero electrical potential.

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

a. A series circuit has one path for current to flow, while a parallel circuit has multiple paths
b. A series circuit has multiple paths for current to flow, while a parallel circuit has one path
c. A series circuit and a parallel circuit are the same things
d. There is no difference between a series circuit and a parallel circuit

A series circuit has one path for current to flow, while a parallel circuit has multiple paths.

## What is the purpose of an electrical relay?

a. To convert AC to DC
b. To convert DC to AC
c. To regulate voltage levels
d. To control the flow of electrical current

The purpose of an electrical relay is to control the flow of electrical current.

## What is the difference between a voltage source and a current source?

a. A voltage source supplies a fixed voltage, while a current source supplies a fixed current
b. A voltage source supplies a fixed current, while a current source supplies a fixed voltage
c. A voltage source and a current source are the same thing
d. There is no difference between a voltage source and a current source

A voltage source supplies a fixed voltage, while a current source supplies a fixed current.

## What is Ohm’s Law?

a. The law that states that the resistance of a conductor is directly proportional to its temperature
b. The law that states that the voltage across a conductor is directly proportional to the current flowing through it
c. The law that states that the current flowing through a conductor is directly proportional to the temperature of the conductor
d. The law that states that the voltage across a conductor is inversely proportional to the current flowing through it

Ohm’s Law states that the voltage across a conductor is directly proportional to the current flowing through it.

## What is a diode?

a. A device that stores electrical energy
b. A device that regulates electrical energy
c. A device that converts AC to DC
d. A device that allows current to flow in one direction only

A diode is a device that allows current to flow in one direction only.

## What is a capacitor?

a. A device that stores electrical energy
b. A device that regulates electrical energy
c. A device that converts AC to DC
d. A device that converts DC to AC

A capacitor is a device that stores electrical energy.

## What is a resistor?

a. A device that stores electrical energy
b. A device that regulates electrical energy
c. A device that converts AC to DC
d. A device that allows current to flow in one direction only

A resistor is a device that regulates electrical energy.

## What is an inductor?

a. A device that stores electrical energy
b. A device that regulates electrical energy
c. A device that converts DC to AC
d. A device that opposes changes in electrical current

An inductor is a device that opposes changes in electrical current.

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

a. To regulate voltage levels
b. To convert AC to DC
c. To protect against electrical overloads
d. To control the flow of electrical current

The purpose of a fuse in an electrical circuit is to protect against electrical overloads.

## What is a transistor?

a. A device that stores electrical energy
b. A device that regulates electrical energy
c. A device that amplifies or switches electrical signals
d. A device that converts DC to AC

Answer: c. A transistor is a device that can be used to amplify or switch electrical signals.

## What is a transformer?

a. A device that converts AC to DC
b. A device that stores electrical energy
c. A device that regulates electrical energy
d. A device that changes the voltage level of an alternating current

A transformer is a device that changes the voltage level of an alternating current.

## What is a relay?

a. A device that stores electrical energy
b. A device that regulates electrical energy
c. A device that amplifies or switches electrical signals
d. A device that controls the flow of electrical current in a circuit

A relay is a device that controls the flow of electrical current in a circuit.

## What is a ground fault circuit interrupter (GFCI)?

a. A device that protects against electrical overloads
b. A device that converts AC to DC
c. A device that detects imbalances in electrical current and shuts off power
d. A device that regulates voltage levels

A GFCI is a device that detects imbalances in electrical current and shuts off power to prevent electric shock.

## What is a solenoid?

a. A device that stores electrical energy
b. A device that amplifies or switches electrical signals
c. A device that converts DC to AC
d. A device that produces a magnetic field when electrical current flows through it

A solenoid is a device that produces a magnetic field when electrical current flows through it.

## What is a potentiometer?

a. A device that regulates electrical energy
b. A device that measures electrical energy
c. A device that amplifies or switches electrical signals
d. A device that can vary the resistance in an electrical circuit

A potentiometer is a device that can vary the resistance in an electrical circuit, often used for volume control in audio equipment.

## What is an oscilloscope?

a. A device that measures electrical energy
b. A device that stores electrical energy
c. A device that amplifies or switches electrical signals
d. A device that displays waveforms of electrical signals

An oscilloscope is a device that displays waveforms of electrical signals, used for testing and troubleshooting electronic circuits.

## What is a three-phase power system?

a. A power system that uses three electrical conductors to distribute power
b. A power system that converts AC to DC
c. A power system that regulates voltage levels
d. A power system that produces a constant voltage output

A three-phase power system is a power system that uses three electrical conductors to distribute power.

## What is an electric generator?

a. A device that converts electrical energy to mechanical energy
b. A device that converts mechanical energy to electrical energy
c. A device that stores electrical energy
d. A device that regulates electrical energy

An electric generator is a device that converts mechanical energy to electrical energy.

## What is a lightning rod?

a. A device that regulates electrical energy
b. A device that converts AC to DC
c. A device that protects against lightning strikes
d. A device that stores electrical energy

A lightning rod is a device that protects buildings and structures from lightning strikes by providing a path for the lightning to travel to the ground.

## What is a surge protector?

a. A device that regulates voltage levels
b. A device that converts AC to DC
c. A device that protects against electrical overloads
d. A device that amplifies or switches electrical signals

A surge protector is a device that protects electrical equipment from voltage spikes and surges, commonly used to protect sensitive electronic devices from damage due to lightning strikes or power surges.

## What is a rectifier?

a. A device that converts DC to AC
b. A device that stores electrical energy
c. A device that changes the voltage level of an AC current
d. A device that converts AC to DC

Answer: d. A rectifier is a device that converts AC to DC.

## What is an integrated circuit?

a. A device that stores electrical energy
b. A device that regulates voltage levels
c. A device that amplifies or switches electrical signals
d. A device that contains multiple electronic components on a single chip

An integrated circuit is a device that contains multiple electronic components on a single chip, often used in computer hardware.

## What is a motor starter?

a. A device that regulates electrical energy
b. A device that stores electrical energy
c. A device that controls the starting and stopping of a motor
d. A device that converts DC to AC

A motor starter is a device that controls the starting and stopping of a motor.

## What is a photovoltaic cell?

a. A device that stores electrical energy
b. A device that converts sunlight into electrical energy
c. A device that amplifies or switches electrical signals
d. A device that regulates electrical energy

A photovoltaic cell is a device that converts sunlight into electrical energy, often used in solar panels.

## What is a wattmeter?

a. A device that measures electrical energy
b. A device that stores electrical energy
c. A device that amplifies or switches electrical signals
d. A device that regulates electrical energy

A wattmeter is a device that measures electrical energy, specifically the rate of energy consumption in a circuit.

## What is a step-up transformer?

a. A transformer that increases the voltage level of an AC current
b. A transformer that decreases the voltage level of an AC current
c. A transformer that converts DC to AC
d. A transformer that regulates voltage levels

A step-up transformer is a transformer that increases the voltage level of an AC current.

## What is an AC motor?

a. A motor that operates on DC power
b. A motor that operates on AC power
c. A motor that can operate on both AC and DC power
d. A motor that converts DC to AC

An AC motor is a motor that operates on AC power.

## What is the difference between a fuse and a circuit breaker?

a. A fuse is mechanical and a circuit breaker is electronic
b. A fuse can be reset and a circuit breaker cannot
c. A fuse is designed for low voltage circuits and a circuit breaker for high voltage circuits
d. A fuse melts and breaks the circuit while a circuit breaker trips and breaks the circuit

A fuse melts and breaks the circuit while a circuit breaker trips and breaks the circuit.

## What is the purpose of a voltage regulator?

a. To convert AC voltage to DC voltage
b. To stabilize and maintain a constant voltage level
c. To amplify the voltage level of a circuit
d. To switch on and off a circuit based on a control signal

The purpose of a voltage regulator is to stabilize and maintain a constant voltage level, commonly used in power supplies and battery chargers.

## What is a superconductor?

a. A material that conducts electricity with zero resistance at very low temperatures
b. A material that conducts electricity with high resistance at room temperature
c. A material that amplifies electrical signals
d. A material that converts AC to DC

A superconductor is a material that conducts electricity with zero resistance at very low temperatures, commonly used in MRI machines and particle accelerators.

## What is the difference between an AC generator and a DC generator?

a. An AC generator produces AC voltage while a DC generator produces DC voltage
b. An AC generator uses magnets to produce voltage while a DC generator uses brushes and commutators
c. An AC generator is more efficient than a DC generator
d. A DC generator is more reliable than an AC generator

An AC generator produces AC voltage while a DC generator produces DC voltage.

## What is the function of a transformer?

a. To convert AC voltage to DC voltage
b. To amplify the voltage of a circuit
c. To regulate the voltage of a circuit
d. To transfer electrical energy from one circuit to another through electromagnetic induction

The function of a transformer is to transfer electrical energy from one circuit to another through electromagnetic induction, commonly used in power transmission and distribution systems.

## What is a circuit?

a. A path that allows electricity to flow between two points
b. A device that regulates electrical energy
c. A device that amplifies or switches electrical signals
d. A device that stores electrical energy

A circuit is a path that allows electricity to flow between two points, typically consisting of a power source, wires, and load.

## What is the difference between AC and DC current?

a. AC current flows in one direction only while DC current changes direction periodically
b. AC current changes direction periodically while DC current flows in one direction only
c. AC current is used for high voltage circuits while DC current is used for low voltage circuits
d. AC current is more efficient than DC current

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

## What is a semiconductor?

a. A material that conducts electricity with zero resistance at very low temperatures
b. A material that conducts electricity with high resistance at room temperature
c. A material that amplifies electrical signals
d. A material that has intermediate electrical conductivity between that of a conductor and an insulator

A semiconductor is a material that has intermediate electrical conductivity between that of a conductor and an insulator, commonly used in electronic circuits and devices.

## What is an amplifier?

a. A device that stores electrical energy
b. A device that amplifies or switches electrical signals
c. A device that converts AC to DC
d. A device that regulates electrical energy

An amplifier is a device that amplifies or switches electrical signals, commonly used in audio and radio equipment.

a) Copper
b) Aluminum
c) Iron
d) Gold

## Which type of motor is most commonly used in industrial applications?

a) DC motor
b) AC induction motor
c) Stepper motor
d) Brushless DC motor

## What is the purpose of a diode in an electrical circuit?

a) To regulate voltage
b) To control current flow
c) To convert AC power to DC power
d) To allow current to flow in only one direction

Answer: d) To allow current to flow in only one direction

## Which law describes the relationship between the current flowing through a conductor and the voltage across it?

b) Ohm’s law
c) Lenz’s law
d) Kirchhoff’s law

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

a) To store electrical energy
b) To convert AC power to DC power
c) To regulate voltage
d) To control current flow

a) Capacitor
b) Resistor
c) Fuse
d) Transistor

## What is the purpose of a relay in an electrical system?

a) To convert AC power to DC power
b) To regulate voltage
c) To control current flow
d) To switch high-power loads using low-power signals

## Which type of power transmission is commonly used for long-distance transmission of electrical power?

a) DC transmission
b) AC transmission
c) Stepper transmission
d) Brushless transmission

## Which law describes the total current flowing into a junction in an electrical circuit?

b) Ohm’s law
c) Lenz’s law
d) Kirchhoff’s current law

## Which type of circuit is used to convert AC power to DC power?

a) Rectifier circuit
b) Amplifier circuit
c) Filter circuit
d) Oscillator circuit

a) Ohms
b) Watts
c) Amperes
d) Volts

## Which type of electrical motor is commonly used in household appliances like blenders and mixers?

a) DC motor
b) AC induction motor
c) Stepper motor
d) Brushless DC motor

## Which law describes the direction of an induced electromotive force?

b) Ohm’s law
c) Lenz’s law
d) Kirchhoff’s voltage law

## What is the function of a transistor in an electrical circuit?

a) To store electrical energy
b) To convert AC power to DC power
c) To regulate voltage
d) To control current flow

a) Voltmeter
b) Ammeter
c) Ohmmeter
d) Wattmeter

## What is the purpose of a circuit breaker in an electrical system?

a) To convert AC power to DC power
b) To regulate voltage
c) To control current flow
d) To protect electrical circuits from overcurrent and short circuits

a) 14-gauge wire
b) 16-gauge wire
c) 18-gauge wire
d) 20-gauge wire

## What is the function of a flyback diode in an electrical circuit?

a) To regulate voltage
b) To control current flow
c) To protect other components from voltage spikes
d) To store electrical energy

## Which type of electrical motor is commonly used in elevators and cranes?

a) DC motor
b) AC induction motor
c) Stepper motor
d) Synchronous motor

## Which law describes the relationship between the voltage across a circuit and the current flowing through it?

b) Ohm’s law
c) Lenz’s law
d) Kirchhoff’s voltage law

## What is the purpose of a resistor in an electrical circuit?

a) To store electrical energy
b) To convert AC power to DC power
c) To regulate voltage
d) To control current flow