What is the purpose of using a flyback diode in a circuit?
A To stabilize voltage
B To protect against voltage spikes
C To amplify current
D To store energy
Flyback diodes are used to prevent voltage spikes across inductive loads, safeguarding components from damage.
What type of signal is represented by a sinusoidal waveform?
A Direct Current (DC)
B Alternating Current (AC)
C Static Current
D Pulsating DC
Alternating current (AC) is represented by a sinusoidal waveform, indicating its periodic nature.
What is the unit of inductance?
A Farad
B Weber
C Henry
D Ohm
Inductance is measured in henries (H), which quantifies the opposition to changes in current.
What happens to a capacitor’s reactance as the frequency of the applied voltage increases?
A Increases
B Decreases
C Remains constant
D Becomes zero
Capacitive reactance (Xc) is inversely proportional to frequency (f), so it decreases as frequency increases.
Which device converts electrical energy into heat energy?
A Heater
B Motor
C Generator
D Inductor
Electric heaters convert electrical energy into heat energy, commonly used for space or water heating.
What is the primary function of a transformer?
A Increase or decrease voltage
B Store electrical energy
C Regulate current
D Convert AC to DC
Transformers are used to step up or step down voltage levels in AC circuits via electromagnetic induction.
What is the SI unit of electric field intensity?
A Volt per meter
B Coulomb per meter
C Newton per coulomb
D Weber per meter
Electric field intensity can be expressed as Volt per meter (V/m) or Newton per coulomb (N/C), as both are equivalent units.
What is the main characteristic of a semiconductor material?
A High conductivity
B High resistivity
C Conductivity between a conductor and an insulator
D Zero resistance
Semiconductor materials like silicon have electrical conductivity between that of conductors and insulators.
What does an oscilloscope display?
A Voltage over time
B Current over time
C Resistance over time
D Power over time
An oscilloscope graphically displays voltage as a function of time, helping analyze electrical signals.
Which principle explains the working of an electric motor?
A Faraday’s Law
B Fleming’s Left-Hand Rule
C Joule’s Law
D Ohm’s Law
Fleming’s Left-Hand Rule explains how current, magnetic field, and force interact in an electric motor to produce motion.
What does Kirchhoff’s Voltage Law (KVL) state?
A The total current entering a junction equals the current leaving it.
B The total voltage around a closed loop is zero.
C Voltage is directly proportional to current.
D Current remains constant in a circuit.
KVL states that the sum of all voltage drops and rises in a closed loop equals zero, ensuring energy conservation.
Which material is commonly used as a dielectric in capacitors?
A Copper
B Paper
C Aluminum
D Silicon
Paper, mica, ceramic, and plastic are common dielectric materials used in capacitors to increase their storage capacity.
What does the term “electromotive force (EMF)” refer to?
A The force between two charges
B The energy supplied by a source per unit charge
C The resistance of a circuit
D The current in a circuit
EMF is the voltage generated by a source like a battery or generator, measured in volts.
Which device protects a circuit from excessive current?
A Inductor
B Capacitor
C Fuse
D Diode
A fuse melts when excessive current flows through it, breaking the circuit and protecting the components.
Which law governs the relationship between force, current, and magnetic field in an electric motor?
A Faraday’s Law
B Lenz’s Law
C Fleming’s Left-Hand Rule
D Kirchhoff’s Law
Fleming’s Left-Hand Rule determines the direction of force acting on a current-carrying conductor in a magnetic field.
What is the purpose of a transformer in an electrical system?
A To generate electricity
B To step up or step down voltage
C To convert AC to DC
D To store energy
Transformers use electromagnetic induction to modify voltage levels for efficient power transmission.
What does the term “impedance” refer to in an AC circuit?
A Opposition to direct current
B Opposition to alternating current
C Voltage drop across a resistor
D Capacitance in the circuit
Impedance is the total opposition to the flow of AC and includes resistance and reactance.
What happens to the total resistance in a parallel circuit when more resistors are added?
A Increases
B Decreases
C Remains the same
D Doubles
Adding resistors in parallel provides additional current paths, reducing the overall resistance of the circuit.
Which component allows current to flow only in one direction?
A Resistor
B Capacitor
C Diode
D Inductor
Diodes allow current to flow in one direction while blocking it in the reverse direction, acting as a one-way valve.
What is the primary purpose of grounding in electrical systems?
A To increase voltage
B To prevent overloading
C To provide a safe path for fault currents
D To regulate power
Grounding prevents electric shock by providing a safe path for excess currents to flow into the earth.
What is the frequency of standard AC supply in India?
A 50 Hz
B 60 Hz
C 100 Hz
D 120 Hz
The standard frequency for AC supply in India is 50 Hz.
Which component stores energy in the form of an electric field?
A Resistor
B Capacitor
C Inductor
D Transformer
Capacitors store electrical energy in the form of an electric field between their plates.
What is the SI unit of electric field strength?
A Weber
B Volt per meter
C Coulomb
D Ampere
Electric field strength is measured in volts per meter (\( \text{V/m} \)).
What is the function of a voltmeter?
A Measure current
B Measure voltage
C Measure resistance
D Measure power
Voltmeters measure the potential difference across a component and are connected in parallel.
What does a current transformer (CT) do?
A Steps up voltage
B Steps down current
C Converts AC to DC
D Stores energy
Current transformers reduce high currents to lower values for safe measurement and monitoring.
Which component is used to oppose sudden changes in current?
A Capacitor
B Resistor
C Inductor
D Diode
Inductors resist changes in current by inducing a back EMF, stabilizing the circuit.
What is the primary function of a resistor in an electrical circuit?
A Increase voltage
B Limit current
C Store charge
D Amplify signals
Resistors control and limit current to protect other components in the circuit.
What happens when a conductor is moved through a magnetic field?
A A force is generated
B A current is induced
C Voltage is decreased
D Resistance increases
Moving a conductor through a magnetic field induces an electromotive force (EMF) and generates current, as per Faraday’s Law.
What is the unit of electrical energy?
A Joule
B Watt
C Ohm
D Volt
Electrical energy is measured in joules, representing the work done to move a charge through a potential difference.
Which type of semiconductor is formed by adding pentavalent impurities?
A N-type
B P-type
C Intrinsic
D Insulator
Adding pentavalent impurities like phosphorus creates N-type semiconductors, with electrons as majority carriers.
What is the relationship between voltage, current, and power in a circuit?
A P = V + I
B P = VI
C P = V / I
D P = V²I
Power (P) in an electrical circuit is calculated as the product of voltage (V) and current (I).
Which material is commonly used for making semiconductor devices?
A Gold
B Silicon
C Aluminum
D Copper
Silicon is widely used in semiconductor devices due to its abundance and excellent electrical properties.
Which of the following represents Ohm’s Law?
A V = IR
B V = I²R
C V = P / I
D V = 1 / R
Ohm’s Law states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, with resistance (R) as the constant of proportionality.
What happens to the current in a circuit if resistance increases while the voltage remains constant?
A Current increases
B Current decreases
C Current remains constant
D Current becomes zero
According to Ohm’s Law (I = V / R), an increase in resistance (R) results in a decrease in current (I) when voltage (V) is constant.
Which device is used to store electrical energy temporarily?
A Inductor
B Capacitor
C Resistor
D Transformer
Capacitors store electrical energy temporarily in the form of an electric field.
What is the primary function of a diode?
A Store electrical energy
B Resist current
C Allow current to flow in one direction
D Step up voltage
Diodes are unidirectional devices that allow current to flow in one direction while blocking it in the reverse direction.
What does a multimeter measure?
A Current only
B Voltage only
C Resistance only
D Voltage, current, and resistance
A multimeter is a versatile tool that measures voltage, current, and resistance in a circuit.
Which of the following is a unit of electrical resistance?
A Coulomb
B Watt
C Ohm
D Henry
Resistance is measured in ohms (Ω), representing the opposition to the flow of current.
What is the main source of energy in a photovoltaic cell?
A Heat
B Magnetic field
C Sunlight
D Chemical reaction
Photovoltaic cells convert sunlight into electrical energy using the photoelectric effect.
Which law states that the sum of currents entering a junction equals the sum of currents leaving it?
A Kirchhoff’s Voltage Law
B Coulomb’s Law
C Kirchhoff’s Current Law
D Faraday’s Law
Kirchhoff’s Current Law ensures the conservation of charge at a junction, where the total current entering equals the total current leaving.
What is the SI unit of electric charge?
A Coulomb
B Ampere
C Joule
D Volt
Electric charge is measured in coulombs (C), with one coulomb being the charge transported by a current of one ampere in one second.
What does the term “electric flux” refer to?
A Flow of electric current
B Total electric field passing through a surface
C Resistance of a circuit
D Voltage drop in a conductor
Electric flux represents the total number of electric field lines passing through a given surface.
Which device converts electrical energy into mechanical energy?
A Generator
B Motor
C Rectifier
D Transformer
Electric motors convert electrical energy into mechanical energy, which is used to perform mechanical work.
What is the relationship between electric field (E) and electric potential (V)?
A E = V²
B E = V / d
C E = Vd
D E = V² / d²
The electric field (E) is the gradient of electric potential (V) over a distance (d), expressed as E = V / d.
What is the primary function of an inductor in a circuit?
A Store energy in an electric field
B Store energy in a magnetic field
C Oppose voltage
D Measure current
Inductors store energy in a magnetic field when current flows through them, opposing changes in current.
What does the term “electric current” represent?
A Voltage applied across a circuit
B Flow of electric charge
C Opposition to voltage
D Potential difference
Electric current is the flow of electric charge through a conductor, measured in amperes (A).
Which property of a material determines its ability to conduct electricity?
A Resistivity
B Permeability
C Capacitance
D Inductance
Resistivity is a material-specific property that quantifies its opposition to the flow of electric current.
What type of circuit allows electricity to flow continuously without interruption?
A Open circuit
B Closed circuit
C Short circuit
D Parallel circuit
In a closed circuit, a complete path is available for current to flow continuously.
Which of the following is NOT an electrical insulator?
A Rubber
B Glass
C Copper
D Plastic
Copper is an excellent conductor of electricity, while rubber, glass, and plastic are insulators.
What does a signal generator produce?
A DC voltage
B Sine, square, or triangular waveforms
C Magnetic fields
D Electric fields
Signal generators produce various waveforms such as sine, square, or triangular for testing and analysis of electrical circuits and devices.