Introduction to Electrical Engineering MCQs (Part-3)
What is the SI unit of voltage?
A Watt
B Volt
C Ampere
D Ohm
The SI unit of voltage is the Volt (V). Voltage is the potential difference between two points in a circuit. It causes current to flow through the conductor and is essential in powering electrical devices.
Which of the following materials is an insulator?
A Gold
B Aluminum
C Copper
D Rubber
Rubber is an insulator, meaning it does not allow the easy flow of electric current. It is commonly used to coat wires and electrical devices to prevent accidental shocks or short circuits.
What is the primary function of a transformer?
A To measure current
B To store energy
C To change voltage
D To convert current
A transformer is used to change the voltage level in an AC circuit. It can either step up (increase) or step down (decrease) the voltage, depending on the turns ratio between its primary and secondary coils.
What is the basic unit of power in electrical systems?
A Watt
B Ohm
C Ampere
D Volt
The basic unit of electrical power is the Watt (W). It is calculated using the formula P=V×I, where power is the rate at which energy is transferred.
Which of the following describes an open circuit?
A Current can flow
B No resistance
C Path is incomplete
D Closed path for current
An open circuit occurs when the path of current is incomplete, meaning current cannot flow. This could be caused by a switch being open, a broken wire, or a disconnected component in the circuit.
What does an ammeter measure?
A Voltage
B Resistance
C Power
D Current
An ammeter is a device used to measure the current flowing through a circuit. It is connected in series with the load to ensure that it measures the entire current passing through the circuit.
What is a primary characteristic of a conductor?
A Blocks current
B Allows current flow
C Stores energy
D High resistance
A conductor is a material that allows the flow of electric current. Metals like copper and aluminum are good conductors because their free electrons can move easily, facilitating the flow of electricity.
What is the purpose of a switch in an electrical circuit?
A To control current flow
B To store power
C To measure energy
D To increase voltage
A switch is used to control the flow of current in a circuit. By opening or closing the switch, you can either interrupt or allow the flow of electricity, thus turning electrical devices on or off.
Which of the following is an example of a semiconductor?
A Aluminum
B Iron
C Copper
D Silicon
Silicon is a semiconductor, meaning it has properties between conductors and insulators. It is used in electronic components like diodes, transistors, and integrated circuits due to its ability to control electrical flow.
What does a potentiometer control?
A Power
B Voltage
C Resistance
D Current
A potentiometer is a variable resistor that allows you to adjust the resistance in a circuit. By changing its resistance, you can control the current and voltage within the circuit, often used for adjusting volume or light intensity.
What is the relationship between resistance and current?
A Directly related to power
B Directly proportional
C Inversely proportional
D Unrelated
According to Ohm’s Law, resistance and current are inversely proportional. As resistance increases in a circuit, the current decreases, assuming constant voltage. This relationship is fundamental to circuit analysis and design.
Which of the following components is used to limit current?
A Resistor
B Diode
C Inductor
D Capacitor
A resistor is used to limit the amount of current flowing through a circuit. It works by offering resistance to the flow of electrons, which reduces the current to a safe and manageable level.
What does the term “AC” stand for in electrical systems?
A Alternating charge
B Alternative current
C Ampere current
D Absolute current
AC stands for Alternating Current. It is an electric current that reverses direction periodically. AC is used in most power distribution systems because it is easy to generate and transmit over long distances.
What is the function of an inductor in a circuit?
A Measure power
B Store voltage
C Store energy
D Measure current
An inductor stores electrical energy in a magnetic field when current flows through it. It resists changes in current, and is used in applications like filters and inductive heating.
What does a voltmeter measure?
A Voltage
B Power
C Resistance
D Current
A voltmeter measures the potential difference (voltage) between two points in a circuit. It is connected in parallel to the circuit component, and is used to ensure voltage levels are within acceptable ranges for safe operation.