Introduction to Electrical Engineering MCQs (Part-10)
Which electrical quantity is measured in amperes?
A Voltage
B Current
C Resistance
D Capacitance
Electric current, which is the rate of flow of electric charge, is measured in amperes (A).
What happens to the total capacitance when capacitors are connected in parallel?
A It increases
B It decreases
C It remains constant
D It becomes zero
When capacitors are connected in parallel, their capacitances add up, increasing the total capacitance of the circuit.
What is the primary function of a resistor in a circuit?
A To increase voltage
B To store electrical energy
C To limit current flow
D To step up current
Resistors are used to control the flow of electric current in a circuit, protecting other components from excessive current.
Which device converts mechanical energy into electrical energy?
A Motor
B Generator
C Rectifier
D Transformer
Generators use electromagnetic induction to convert mechanical energy into electrical energy.
What does a capacitor do in a DC circuit?
A Blocks DC and allows AC
B Blocks AC and allows DC
C Increases resistance
D Amplifies voltage
Capacitors block direct current (DC) but allow alternating current (AC) to pass through due to the charging and discharging of their plates.
What is the unit of power in an electrical system?
A Joule
B Watt
C Volt
D Ampere
Power in electrical systems is measured in watts (W), which indicates the rate at which energy is consumed or produced.
What happens to the magnetic field strength inside a coil when the current is increased?
A Increases
B Decreases
C Remains the same
D Becomes zero
The magnetic field strength inside a coil is directly proportional to the current passing through it, so increasing the current strengthens the magnetic field.
What is the function of a rectifier?
A Convert DC to AC
B Convert AC to DC
C Store electrical energy
D Increase current
Rectifiers are used to convert alternating current (AC) into direct current (DC), which is required for many electronic devices.
Which law states that the induced EMF opposes the change in magnetic flux?
A Ohm’s Law
B Kirchhoff’s Law
C Lenz’s Law
D Faraday’s Law
Lenz’s Law states that the direction of the induced EMF is such that it opposes the change in magnetic flux that caused it.
What is the purpose of a circuit breaker?
A Store charge
B Prevent overloading or short circuits
C Measure current
D Increase voltage
Circuit breakers disconnect power automatically during overloading or short circuits to protect the system.
What is the SI unit of inductance?
A Ohm
B Tesla
C Henry
D Farad
Inductance, which measures the ability of a conductor to store energy in a magnetic field, is measured in henries (H).
What does a zener diode primarily do in a circuit?
A Amplifies current
B Converts AC to DC
C Stabilizes voltage
D Regulates current
Zener diodes maintain a constant output voltage across their terminals, making them useful for voltage regulation.
What is the purpose of an ammeter?
A To measure voltage
B To measure resistance
C To measure current
D To measure power
Ammeters measure the electric current flowing through a circuit and are connected in series.
What is the typical value of AC supply voltage in households in India?
A 110 V
B 220 V
C 240 V
D 50 V
The standard AC voltage supply in Indian households is 240 V at a frequency of 50 Hz.
Which of the following is NOT a renewable energy source?
A Solar power
B Wind power
C Fossil fuels
D Hydropower
Fossil fuels like coal and oil are non-renewable energy sources because they take millions of years to form and are depleted faster than they regenerate.
What is the main purpose of a signal generator?
A Measure voltage
B Generate waveforms for testing
C Store electrical energy
D Increase current
Signal generators produce different waveforms, such as sine, square, or triangular, for testing and analysis of electronic circuits.
Which of the following is a good conductor of electricity?
A Rubber
B Glass
C Copper
D Wood
Copper is widely used for electrical wiring due to its excellent conductivity and low resistivity.
What does the term “short circuit” refer to?
A A circuit with low resistance causing high current flow
B A circuit with high resistance blocking current
C A circuit with no voltage
D A disconnected circuit
A short circuit occurs when there is an unintended low-resistance path in a circuit, leading to excessive current flow.
What is the purpose of an isolator in electrical systems?
A Increase voltage
B Protect against overcurrent
C Disconnect a circuit for maintenance
D Store electrical energy
Isolators are used to safely disconnect a circuit from the power supply during maintenance or repair work.
What does the term “electric potential difference” refer to?
A The force between two charges
B The work done to move a charge between two points
C The opposition to current flow
D The power dissipated in a circuit
Electric potential difference is the work done per unit charge to move a charge from one point to another, measured in volts.