Q.1 Which of the following components is a passive two-terminal electrical component?
Resistor
Capacitor
Inductor
All of the above
Explanation - Resistor, capacitor, and inductor are all passive two‑terminal components.
Correct answer is: All of the above
Q.2 A resistor that limits current in a circuit is called a/an:
Ground
Load
Resistor
Switch
Explanation - Resistors are used to control current flow.
Correct answer is: Resistor
Q.3 What unit is used to measure electrical resistance?
Volts
Amps
Ohms
Watts
Explanation - Resistance is measured in ohms (Ω).
Correct answer is: Ohms
Q.4 Which symbol represents a battery in a circuit diagram?
A straight line with a short dash
Two parallel lines of different lengths
A circle with a plus sign
A triangle
Explanation - A battery is depicted by two parallel lines, one longer than the other.
Correct answer is: Two parallel lines of different lengths
Q.5 Which law states that the sum of the currents entering a junction equals the sum of the currents leaving?
Kirchhoff's Voltage Law
Kirchhoff's Current Law
Ohm's Law
Faraday's Law
Explanation - Kirchhoff's Current Law (KCL) deals with current conservation at a node.
Correct answer is: Kirchhoff's Current Law
Q.6 What does Ohm's Law relate?
Power, voltage, and resistance
Current, voltage, and resistance
Current, power, and time
Voltage, power, and current
Explanation - Ohm's Law states I = V/R.
Correct answer is: Current, voltage, and resistance
Q.7 A circuit component that stores electrical energy in an electric field is a:
Resistor
Capacitor
Inductor
Diode
Explanation - Capacitors store energy in an electric field between plates.
Correct answer is: Capacitor
Q.8 Which device allows current to flow in one direction only?
Resistor
Capacitor
Inductor
Diode
Explanation - Diodes permit current in only one direction.
Correct answer is: Diode
Q.9 A switch that is closed allows:
No current flow
Current flow
Only AC current
Only DC current
Explanation - A closed switch completes the circuit, allowing current.
Correct answer is: Current flow
Q.10 What is the term for the amount of charge passing through a point per second?
Resistance
Voltage
Current
Power
Explanation - Current (I) is charge per unit time, measured in amperes.
Correct answer is: Current
Q.11 Which component is used to protect a circuit from excess current?
Fuse
Capacitor
Inductor
Transformer
Explanation - A fuse melts when current exceeds safe limits, breaking the circuit.
Correct answer is: Fuse
Q.12 A circuit that is not connected to a power source has which of the following?
No voltage drop across components
Zero current flow
Negative voltage
Positive voltage
Explanation - Without a source, no current flows.
Correct answer is: Zero current flow
Q.13 Which type of resistor changes resistance with temperature?
Carbon film
Metal film
Thermistors
Light‑emitting diode
Explanation - Thermistors exhibit resistance that varies significantly with temperature.
Correct answer is: Thermistors
Q.14 When two resistors are connected in series, the total resistance is:
The greater of the two
The lesser of the two
The sum of both resistances
Half of the greater resistance
Explanation - Series resistors add: R_total = R1 + R2.
Correct answer is: The sum of both resistances
Q.15 When two resistors are connected in parallel, the total resistance is:
The larger of the two
The smaller of the two
The reciprocal of the sum of reciprocals
The product of both resistances
Explanation - Parallel resistors follow 1/R_total = 1/R1 + 1/R2.
Correct answer is: The reciprocal of the sum of reciprocals
Q.16 In a DC circuit, the potential difference across a resistor is zero when:
There is a current flow
The resistor is shorted
No current flows through it
The resistor is open
Explanation - If I = 0, then V = IR = 0.
Correct answer is: No current flows through it
Q.17 Which equation correctly calculates power dissipation in a resistor?
P = V + I
P = V × I
P = V ÷ I
P = I ÷ V
Explanation - Power equals voltage times current.
Correct answer is: P = V × I
Q.18 A capacitor connected across a battery will eventually reach:
Zero voltage
Battery voltage
Half of battery voltage
Double the battery voltage
Explanation - Capacitor charges until its voltage equals the source voltage.
Correct answer is: Battery voltage
Q.19 Which law describes the conservation of energy in an electrical circuit?
Kirchhoff's Voltage Law
Kirchhoff's Current Law
Ohm's Law
Kirchhoff's Power Law
Explanation - KVL ensures the sum of voltage drops equals the source voltage.
Correct answer is: Kirchhoff's Voltage Law
Q.20 A series circuit has the same current flowing through all components because:
They all have the same resistance
The current path is continuous
The voltage is divided
The power is shared equally
Explanation - Series connection forces the same current through each element.
Correct answer is: The current path is continuous
Q.21 An inductor resists changes in current because of:
Its resistance
Its magnetic field
Its capacitance
Its voltage rating
Explanation - Inductors store energy in magnetic fields, opposing current changes.
Correct answer is: Its magnetic field
Q.22 A circuit that includes an inductor and a capacitor can produce:
Only DC
Only AC
Resonance at a particular frequency
No current
Explanation - LC circuits resonate when L and C form a resonant frequency.
Correct answer is: Resonance at a particular frequency
Q.23 Which component is used to smooth out voltage in a power supply?
Resistor
Capacitor
Inductor
Diode
Explanation - Capacitors filter ripple by storing and releasing charge.
Correct answer is: Capacitor
Q.24 In a parallel circuit, the voltage across each branch is:
Different for each branch
The same
Half of the source voltage
Zero
Explanation - All parallel branches share the same potential difference.
Correct answer is: The same
Q.25 Which of the following best explains the function of a fuse?
To limit voltage
To limit current
To store energy
To regulate frequency
Explanation - A fuse melts when current exceeds its rating, protecting the circuit.
Correct answer is: To limit current
Q.26 A resistor’s color code of red, red, orange, gold indicates a resistance of:
22 Ω
220 Ω
2.2 kΩ
22 kΩ
Explanation - Red=2, red=2, orange=10^3, gold=5% tolerance => 22×10^3Ω=2.2kΩ.
Correct answer is: 2.2 kΩ
Q.27 Which equation gives the total power delivered by a source in terms of current and internal resistance?
P = I^2 × R_internal
P = V^2 / R_internal
P = V × I
P = I / R_internal
Explanation - Power dissipated in an internal resistor is I^2R.
Correct answer is: P = I^2 × R_internal
Q.28 A circuit with a single source and multiple branches is known as a/an:
Series circuit
Parallel circuit
Mixed circuit
Open circuit
Explanation - Both series and parallel elements coexist.
Correct answer is: Mixed circuit
Q.29 Which of these is NOT a type of diode?
Zener diode
Light Emitting Diode (LED)
Thermistor diode
Schottky diode
Explanation - Thermistors are resistors; there is no 'thermistor diode'.
Correct answer is: Thermistor diode
Q.30 When a capacitor is fully charged, the current through it is:
Maximum
Zero
Half the source current
Constant non‑zero
Explanation - A fully charged capacitor behaves like an open circuit.
Correct answer is: Zero
Q.31 Which component is commonly used to convert AC to DC?
Resistor
Capacitor
Transformer
Rectifier
Explanation - Rectifiers (diodes or bridge circuits) convert AC to DC.
Correct answer is: Rectifier
Q.32 In a transformer, the turns ratio determines:
Voltage ratio
Current ratio
Power ratio
All of the above
Explanation - Turns ratio defines relationships between voltage, current, and power.
Correct answer is: All of the above
Q.33 Which equation represents the voltage division rule for two series resistors?
V1 = V_total × R2 / (R1+R2)
V1 = V_total × R1 / (R1+R2)
V1 = V_total / (R1+R2)
V1 = V_total × (R1+R2)
Explanation - Voltage drops across a resistor are proportional to its resistance.
Correct answer is: V1 = V_total × R1 / (R1+R2)
Q.34 Which component in a circuit typically has the highest impedance at low frequencies?
Capacitor
Inductor
Resistor
Diode
Explanation - Capacitive reactance Xc = 1/(2πfC) is high at low f.
Correct answer is: Capacitor
Q.35 The time constant of an RC circuit is:
R + C
R × C
R / C
C / R
Explanation - τ = RC determines how fast a capacitor charges/discharges.
Correct answer is: R × C
Q.36 Which of the following is a property of an ideal transformer?
No voltage drop across primary
Infinite turns ratio
Zero losses
All of the above
Explanation - Ideal transformers assume no losses and perfect coupling.
Correct answer is: All of the above
Q.37 The impedance of a capacitor is given by:
Z = 1/jωC
Z = jωC
Z = R + jωL
Z = R - jωC
Explanation - Capacitive impedance decreases with frequency.
Correct answer is: Z = 1/jωC
Q.38 Which component is used to convert variable AC signals to a fixed DC voltage in a radio?
Mixer
Amplifier
Rectifier
Oscillator
Explanation - Rectifiers produce a DC signal from AC for further processing.
Correct answer is: Rectifier
Q.39 Which of the following represents a series LC resonant circuit’s impedance at resonance?
Zero
Maximum
R (resistance)
Infinite
Explanation - At resonance, inductive and capacitive reactances cancel, leaving only resistance.
Correct answer is: Zero
Q.40 If a circuit’s load resistance equals the internal resistance of the source, the power delivered to the load is:
Maximum
Zero
Half the source’s power
Double the source’s power
Explanation - Maximum power transfer occurs when R_load = R_source.
Correct answer is: Maximum
Q.41 Which law states that the sum of the electromotive forces in any closed loop equals the sum of the voltage drops?
Kirchhoff's Voltage Law
Ohm's Law
Faraday's Law
Maxwell's Law
Explanation - KVL is a statement of energy conservation in circuits.
Correct answer is: Kirchhoff's Voltage Law
Q.42 Which element provides a reference point of zero potential in a circuit diagram?
Ground
Neutral
Battery
Switch
Explanation - Ground is the reference potential for all other nodes.
Correct answer is: Ground
Q.43 Which of these is a characteristic of a diode’s forward bias region?
High resistance
Low resistance
Zero current
Infinite voltage drop
Explanation - In forward bias, diodes conduct with a small voltage drop.
Correct answer is: Low resistance
Q.44 An RLC circuit with a resistor, an inductor, and a capacitor all in series has a total impedance of:
R + j(ωL - 1/ωC)
R - j(ωL + 1/ωC)
R × (ωL - 1/ωC)
R / (ωL + 1/ωC)
Explanation - Impedance is the sum of real and imaginary components.
Correct answer is: R + j(ωL - 1/ωC)
Q.45 The resonant frequency of a parallel LC circuit is determined by:
f = 1/(2π√(LC))
f = 2π√(LC)
f = LC
f = 1/(LC)
Explanation - Parallel LC resonance occurs at the natural frequency of the circuit.
Correct answer is: f = 1/(2π√(LC))
Q.46 In power electronics, a MOSFET is primarily used for:
Signal amplification
Voltage regulation
High‑frequency switching
AC to DC conversion
Explanation - MOSFETs act as fast switches in DC‑DC converters.
Correct answer is: High‑frequency switching
Q.47 A transistor in common‑emitter configuration provides:
Voltage gain
Current gain
Power gain
All of the above
Explanation - Common‑emitter amplifies voltage, current, and power.
Correct answer is: All of the above
Q.48 Which of the following statements about inductors is correct?
They store energy in an electric field
Their reactance increases with frequency
They have negligible resistance
They are only used in DC circuits
Explanation - Inductive reactance XL = ωL grows with frequency.
Correct answer is: Their reactance increases with frequency
Q.49 A capacitor’s reactance decreases as frequency increases because:
Capacitance increases
Voltage increases
Impedance formula has inverse dependence on frequency
Resistance increases
Explanation - Xc = 1/(2πfC) → higher f → lower reactance.
Correct answer is: Impedance formula has inverse dependence on frequency
Q.50 Which of these is NOT a form of power factor correction?
Adding a capacitor bank
Adding an inductor bank
Adding a resistor bank
Using a phase‑shift transformer
Explanation - Resistors dissipate power; they don’t correct power factor.
Correct answer is: Adding a resistor bank
Q.51 In a three‑phase system, the line voltage is related to phase voltage by:
V_line = √3 × V_phase
V_line = V_phase / √3
V_line = V_phase
V_line = 2 × V_phase
Explanation - For balanced load, line voltage is √3 times phase voltage.
Correct answer is: V_line = √3 × V_phase
Q.52 A diode that can withstand a reverse voltage of 200V but only 0.7V forward is:
Zener diode
Standard silicon diode
Schottky diode
Light‑emitting diode (LED)
Explanation - Standard diodes have low forward drop and high reverse rating.
Correct answer is: Standard silicon diode
Q.53 The impedance of an inductor in AC is:
Z = R + jωL
Z = R - jωL
Z = jωL
Z = 1/(jωC)
Explanation - Inductor reactance is purely imaginary and increases with frequency.
Correct answer is: Z = jωL
Q.54 A voltage divider built from two equal resistors across 12V will produce:
6V
12V
3V
0V
Explanation - Each resistor drops half the voltage: 12V/2 = 6V.
Correct answer is: 6V
Q.55 An open circuit is defined by:
Zero resistance
Zero voltage
Infinite resistance
Zero current
Explanation - An open circuit blocks current flow entirely.
Correct answer is: Infinite resistance
Q.56 Which component is used to store electrical energy in a magnetic field?
Capacitor
Resistor
Inductor
Diode
Explanation - Inductors store energy magnetically.
Correct answer is: Inductor
Q.57 A circuit element that offers a constant voltage drop regardless of current is a:
Resistor
Battery
Voltage source
Switch
Explanation - A battery supplies a fixed emf to the circuit.
Correct answer is: Battery
Q.58 Which law ensures that charge is conserved at a node?
Kirchhoff's Current Law
Kirchhoff's Voltage Law
Ohm's Law
Faraday's Law
Explanation - KCL states current entering equals current leaving at a node.
Correct answer is: Kirchhoff's Current Law
Q.59 The voltage drop across a resistor is directly proportional to:
Current
Resistance
Both A and B
Frequency
Explanation - Ohm's law: V = IR, so V ∝ I and V ∝ R.
Correct answer is: Both A and B
Q.60 What is the role of a capacitor in a radio's tuning circuit?
Amplify the signal
Filter the signal
Store energy
Change the frequency response
Explanation - Capacitors, together with inductors, select a particular frequency.
Correct answer is: Change the frequency response
Q.61 The unit of inductance is:
Henries
Farads
Ohms
Volts
Explanation - Inductance is measured in henries (H).
Correct answer is: Henries
Q.62 Which component has a fixed resistance regardless of temperature?
Carbon resistor
Metal film resistor
Wire wound resistor
None of the above
Explanation - Wire wound resistors have minimal temperature coefficient.
Correct answer is: Wire wound resistor
Q.63 In a circuit, the voltage across a capacitor in steady DC is:
Zero
Equal to the source voltage
Half the source voltage
Double the source voltage
Explanation - A fully charged capacitor blocks DC, so V_C = V_source.
Correct answer is: Equal to the source voltage
Q.64 When a switch opens in a circuit containing a capacitor, the capacitor:
Immediately discharges
Remains charged for a long time
Starts charging again
Shorts out
Explanation - Without a discharge path, the capacitor holds its charge.
Correct answer is: Remains charged for a long time
Q.65 The resistance of a conductor is directly proportional to:
Length
Cross‑sectional area
Temperature
Both A and C
Explanation - R ∝ L and increases with temperature.
Correct answer is: Both A and C
Q.66 Which of the following is a characteristic of a linear resistor?
Non‑linear V‑I curve
Constant resistance regardless of voltage
Temperature dependent
Capacitive behavior
Explanation - Linear resistors obey Ohm's law with a straight‑line V‑I graph.
Correct answer is: Constant resistance regardless of voltage
Q.67 What does the 'tolerance' on a resistor indicate?
Exact resistance value
Maximum permissible voltage
Allowed deviation from nominal resistance
Temperature range
Explanation - Tolerance specifies how far the actual value can vary.
Correct answer is: Allowed deviation from nominal resistance
Q.68 A resistor with a color code of green, blue, red, gold indicates a resistance of:
5.6 kΩ
3.4 kΩ
6.3 kΩ
4.5 kΩ
Explanation - Green=6, blue=3, red=10^2, gold=5% tolerance ⇒ 63×10^2Ω = 6.3kΩ.
Correct answer is: 6.3 kΩ
Q.69 Which component is used to limit the current surge at the start of a circuit?
Resistor
Inductor
Capacitor
Diode
Explanation - Inductors oppose sudden current changes due to their inductive reactance.
Correct answer is: Inductor
Q.70 A parallel circuit with multiple branches will have:
Higher total resistance than any individual branch
Lower total resistance than any individual branch
Same total resistance as any individual branch
No total resistance
Explanation - Adding paths decreases overall resistance.
Correct answer is: Lower total resistance than any individual branch
Q.71 Which equation gives the total current supplied by a source in a parallel circuit?
I_total = V / ΣR
I_total = Σ(V/R)
I_total = V × ΣR
I_total = Σ(V × R)
Explanation - Total current is the sum of currents through each branch.
Correct answer is: I_total = Σ(V/R)
Q.72 The power dissipated in a resistor can be expressed as:
P = I^2 × R
P = V^2 / R
Both A and B
None of the above
Explanation - Both forms are derived from Ohm's law.
Correct answer is: Both A and B
Q.73 The term 'ground' in a circuit refers to:
The point of maximum voltage
The point of zero potential
The point with highest current
The point with highest resistance
Explanation - Ground is the reference node at 0 V.
Correct answer is: The point of zero potential
Q.74 A diode’s I‑V curve is best described as:
A straight line
An exponential curve
A sinusoid
A constant voltage drop
Explanation - Diode current increases exponentially with forward voltage.
Correct answer is: An exponential curve
Q.75 Which of the following is NOT a type of capacitor?
Ceramic
Tantalum
Inductor
Electrolytic
Explanation - Inductor is a different component, not a capacitor.
Correct answer is: Inductor
Q.76 A capacitor in an AC circuit behaves as:
A short circuit at all frequencies
An open circuit at all frequencies
A voltage source
An impedance that decreases with frequency
Explanation - Capacitive reactance Xc = 1/(2πfC) decreases as frequency increases.
Correct answer is: An impedance that decreases with frequency
Q.77 If a resistor has a resistance of 10 Ω and is connected across a 5 V supply, the current through it is:
0.5 A
0.2 A
5 A
10 A
Explanation - I = V/R = 5V/10Ω = 0.5 A.
Correct answer is: 0.5 A
Q.78 Which device can act as a variable resistor?
Potentiometer
Fuse
Diode
Capacitor
Explanation - A potentiometer allows adjustment of resistance.
Correct answer is: Potentiometer
Q.79 In a DC circuit, a series connection of a battery and a resistor results in:
Zero voltage drop across the resistor
Voltage drop equal to the battery’s emf
No current flow
Infinite current flow
Explanation - The resistor consumes the full battery voltage.
Correct answer is: Voltage drop equal to the battery’s emf
Q.80 Which of the following is a direct consequence of Ohm's Law?
Voltage is the product of current and resistance
Current is the product of voltage and resistance
Power equals resistance times current
Resistance is voltage divided by current
Explanation - Ohm’s law: V = IR.
Correct answer is: Voltage is the product of current and resistance
Q.81 A capacitor’s capacitance is measured in:
Ohms
Farads
Henries
Volts
Explanation - Capacitance is measured in farads (F).
Correct answer is: Farads
Q.82 Which component is used to convert AC voltage from a high to a lower level?
Transformer
Capacitor
Inductor
Resistor
Explanation - Transformers step voltage up or down via magnetic coupling.
Correct answer is: Transformer
Q.83 Which law ensures the sum of currents entering a junction equals the sum leaving it?
Kirchhoff's Current Law
Kirchhoff's Voltage Law
Ohm's Law
Faraday's Law
Explanation - KCL states current conservation at nodes.
Correct answer is: Kirchhoff's Current Law
Q.84 A resistor in series with a battery will:
Create a voltage drop across itself
Double the battery voltage
Block current flow entirely
Short the circuit
Explanation - Resistors consume part of the supply voltage.
Correct answer is: Create a voltage drop across itself
Q.85 The impedance of a circuit containing a resistor and a capacitor in series is:
Z = R + j1/ωC
Z = R - j1/ωC
Z = R × 1/ωC
Z = R / 1/ωC
Explanation - Capacitive reactance is jXc = 1/(jωC).
Correct answer is: Z = R + j1/ωC
Q.86 A capacitor connected across a resistor in an RC circuit will:
Short the resistor
Open the circuit
Create a time delay in current
Increase the resistor value
Explanation - The capacitor charges over time, affecting current flow.
Correct answer is: Create a time delay in current
Q.87 When a switch closes, current begins to flow in a circuit with an inductor because:
Inductor blocks all current
Inductor resists sudden current change
Inductor stores current instantly
Inductor becomes a short circuit immediately
Explanation - Inductors oppose abrupt changes in current.
Correct answer is: Inductor resists sudden current change
Q.88 Which of the following is a non‑linear resistor?
Carbon film resistor
Thermistor
Metal film resistor
Wire wound resistor
Explanation - Thermistors have resistance that varies with temperature.
Correct answer is: Thermistor
Q.89 If a capacitor is fully charged in a DC circuit, what is the voltage across it?
Zero
Half the supply voltage
The same as the supply voltage
Double the supply voltage
Explanation - A fully charged capacitor blocks DC and equals the supply voltage.
Correct answer is: The same as the supply voltage
Q.90 What is the relationship between voltage and current in a perfect conductor?
Voltage is proportional to current
Voltage is zero regardless of current
Current is zero regardless of voltage
Voltage and current are unrelated
Explanation - Perfect conductors have zero resistance, so V = IR = 0.
Correct answer is: Voltage is zero regardless of current
Q.91 Which component will limit the rise time of a digital signal?
Resistor
Capacitor
Inductor
Diode
Explanation - Capacitors can filter high‑frequency components, slowing transitions.
Correct answer is: Capacitor
Q.92 In a parallel RC circuit, the impedance magnitude at frequency f is:
√(R^2 + (1/(ωC))^2)
R × 1/(ωC)
R + 1/(ωC)
R / (1/(ωC))
Explanation - Impedance is the vector sum of resistance and capacitive reactance.
Correct answer is: √(R^2 + (1/(ωC))^2)
Q.93 Which type of diode is designed to block reverse current in high‑voltage applications?
Standard diode
Zener diode
Schottky diode
Light‑emitting diode
Explanation - Zener diodes are used for voltage regulation and reverse blocking.
Correct answer is: Zener diode
Q.94 In a transformer, if the primary has 100 turns and the secondary has 200 turns, the voltage ratio is:
1:2
2:1
100:200
200:100
Explanation - Voltage ratio equals turns ratio: V_s/V_p = N_s/N_p = 200/100 = 2.
Correct answer is: 1:2
Q.95 Which of the following represents an AC voltage source?
DC battery
AC transformer output
Resistor
Capacitor
Explanation - AC sources produce alternating voltage.
Correct answer is: AC transformer output
Q.96 Which circuit element has the property of storing electrical charge between two plates?
Resistor
Capacitor
Inductor
Diode
Explanation - Capacitors store energy in an electric field.
Correct answer is: Capacitor
Q.97 A circuit that contains a resistor, a capacitor, and a resistor connected in parallel has which of the following?
Series connection
Parallel connection
Series‑parallel (mixed) connection
Only a single resistor
Explanation - It involves both series and parallel elements.
Correct answer is: Series‑parallel (mixed) connection
Q.98 The 'tolerance' of a resistor indicates its:
Temperature coefficient
Maximum power rating
Allowed variation from nominal value
Maximum voltage it can handle
Explanation - Tolerance shows how far the actual resistance may differ.
Correct answer is: Allowed variation from nominal value
Q.99 If a DC circuit has a voltage source of 12V and a load of 6Ω, what is the power delivered to the load?
12 W
24 W
6 W
48 W
Explanation - P = V^2/R = 12^2/6 = 24 W.
Correct answer is: 24 W
Q.100 Which component is used to provide a fixed voltage drop regardless of current?
Resistor
Voltage regulator
Zener diode
Inductor
Explanation - Zener diodes maintain a nearly constant voltage across them in reverse breakdown.
Correct answer is: Zener diode
Q.101 In a complex network, the theorem that allows analysis by considering each independent source separately is called:
Norton’s Theorem
Superposition Theorem
Thevenin’s Theorem
Kirchhoff’s Law
Explanation - Superposition permits analyzing each source in isolation.
Correct answer is: Superposition Theorem
Q.102 The characteristic equation of an LC resonant circuit in terms of its natural frequency ω₀ is:
ω₀ = 1/√(LC)
ω₀ = √(LC)
ω₀ = L/C
ω₀ = C/L
Explanation - The resonant angular frequency is ω₀ = 1/√(LC).
Correct answer is: ω₀ = 1/√(LC)
Q.103 Which of the following is the best representation of a voltage divider in a series circuit?
V_out = V_in × R2 / (R1 + R2)
V_out = V_in × (R1 + R2)
V_out = V_in / (R1 + R2)
V_out = V_in × R1 / (R1 + R2)
Explanation - Voltage divides in proportion to resistance.
Correct answer is: V_out = V_in × R2 / (R1 + R2)
Q.104 An ideal diode has which of the following properties?
Zero forward voltage drop
Zero reverse leakage
Infinite forward resistance
Zero reverse breakdown voltage
Explanation - Ideal diodes conduct with no voltage drop forward and block fully reverse.
Correct answer is: Zero forward voltage drop
Q.105 Which of the following devices is commonly used as a switch in digital logic circuits?
Transistor
Capacitor
Inductor
Resistor
Explanation - Transistors act as fast electronic switches.
Correct answer is: Transistor
Q.106 Which type of network is formed by combining series and parallel elements?
Tree network
Mesh network
Mixed network
Linear network
Explanation - Mixed networks contain both series and parallel branches.
Correct answer is: Mixed network
Q.107 The concept of 'power factor' is relevant in AC circuits because it describes the:
Ratio of real power to apparent power
Ratio of reactive power to real power
Ratio of voltage to current
Ratio of current to voltage
Explanation - Power factor indicates how effectively the current is in phase with voltage.
Correct answer is: Ratio of real power to apparent power
Q.108 Which of the following is a property of an ideal inductor?
Zero resistance
Infinite resistance
Fixed inductance regardless of current
Zero inductance
Explanation - Ideal inductors have no series resistance.
Correct answer is: Zero resistance
Q.109 Which equation relates the inductance of a solenoid to its physical parameters?
L = μ₀n²A / l
L = μ₀l / n²A
L = μ₀nA / l
L = μ₀l / nA
Explanation - Inductance depends on permeability, turns squared, area, and length.
Correct answer is: L = μ₀n²A / l
Q.110 Which component is used to provide isolation between primary and secondary circuits in a transformer?
Core
Windings
Load
Switch
Explanation - The magnetic core couples the windings and provides isolation.
Correct answer is: Core
Q.111 In a DC circuit, the 'short circuit' condition occurs when:
The total resistance is infinite
The total resistance is zero
The current is zero
The voltage is zero
Explanation - A short circuit has negligible resistance, allowing large current.
Correct answer is: The total resistance is zero
Q.112 What is the result of connecting a capacitor in series with an inductor in an AC circuit at resonance?
Impedance becomes zero
Impedance becomes infinite
Impedance equals the resistance only
Impedance doubles
Explanation - At resonance, inductive and capacitive reactances cancel out.
Correct answer is: Impedance becomes zero
Q.113 Which type of diode is characterized by a very low forward voltage drop and high current handling?
Zener diode
Schottky diode
Light‑emitting diode
Tunnel diode
Explanation - Schottky diodes have low Vf and high current capability.
Correct answer is: Schottky diode
Q.114 What does the 'impedance' of a circuit element represent in AC analysis?
Only resistance
Resistance and capacitance
Resistance and inductance
Complex resistance (including reactance)
Explanation - Impedance combines resistance and reactive components.
Correct answer is: Complex resistance (including reactance)
Q.115 In a power distribution network, which component is typically used to step up the voltage?
Step‑down transformer
Step‑up transformer
Capacitor bank
Inductor
Explanation - Step‑up transformers increase voltage levels for efficient transmission.
Correct answer is: Step‑up transformer
Q.116 Which of the following best describes the concept of 'load factor' in an electrical system?
The ratio of peak load to average load
The ratio of maximum load to average load
The ratio of instantaneous power to rated power
The ratio of apparent power to real power
Explanation - Load factor measures utilization of capacity over time.
Correct answer is: The ratio of maximum load to average load
Q.117 Which of the following devices can act as a passive filter in an AC circuit?
Resistor
Capacitor
Inductor
All of the above
Explanation - Resistors, capacitors, and inductors can all filter signals in various configurations.
Correct answer is: All of the above
Q.118 What is the primary function of a 'bridge rectifier'?
To step voltage down
To convert AC to DC
To filter noise
To regulate current
Explanation - A bridge rectifier uses four diodes to produce DC from AC.
Correct answer is: To convert AC to DC
Q.119 In a DC circuit, the power dissipated in a resistor can also be calculated as:
P = V^2 / R
P = R / V
P = V × R
P = R × I
Explanation - Using Ohm's law, P = I^2R = V^2/R.
Correct answer is: P = V^2 / R
Q.120 The 'phase angle' between voltage and current in an AC circuit is due to the presence of:
Only resistance
Only inductance
Only capacitance
Inductance or capacitance
Explanation - Reactance causes the current to lead or lag voltage.
Correct answer is: Inductance or capacitance
Q.121 A 'sine wave' in AC circuits is characterized by which of the following?
A constant amplitude and frequency
Random amplitude variations
Constant DC offset
Only zero crossings
Explanation - Sine waves have smooth, periodic variation with fixed amplitude and frequency.
Correct answer is: A constant amplitude and frequency
Q.122 Which of the following components can be used to provide a reference voltage in an amplifier circuit?
Voltage divider
Zener diode
Capacitor
Inductor
Explanation - A Zener diode provides a stable reference voltage in reverse breakdown.
Correct answer is: Zener diode
Q.123 What is the function of a 'snubber circuit' in power electronics?
To reduce voltage spikes
To increase current flow
To filter AC noise
To step down voltage
Explanation - Snubbers protect switches from transients.
Correct answer is: To reduce voltage spikes
Q.124 In the context of AC circuits, which term describes the ratio of voltage to current magnitude?
Voltage drop
Current magnitude
Impedance
Power factor
Explanation - Impedance is the ratio V/I in AC circuits.
Correct answer is: Impedance
Q.125 Which device is used to convert a high‑frequency AC signal into a DC voltage?
Transformer
Rectifier
Inverter
Oscillator
Explanation - Rectifiers remove AC components to produce DC.
Correct answer is: Rectifier
Q.126 In a circuit with multiple voltage sources, which theorem allows the replacement of the network with a single equivalent voltage source?
Thevenin's Theorem
Norton's Theorem
Superposition Theorem
Kirchhoff's Law
Explanation - Thevenin’s theorem simplifies circuits to a single source and resistance.
Correct answer is: Thevenin's Theorem
Q.127 Which of the following best describes the 'resonant frequency' of a parallel LC circuit?
It is when the impedance is minimal
It is when the impedance is maximal
It is when the reactance of L equals the reactance of C
It is when the resistor is zero
Explanation - At resonance, XL = XC, canceling reactances.
Correct answer is: It is when the reactance of L equals the reactance of C
Q.128 Which of the following is a property of a 'low‑pass filter'?
It allows high‑frequency signals to pass
It blocks low‑frequency signals
It attenuates signals above a cutoff frequency
It amplifies signals above a cutoff frequency
Explanation - Low‑pass filters reduce high‑frequency components.
Correct answer is: It attenuates signals above a cutoff frequency
Q.129 Which of the following is the correct formula for the time constant τ of an RC low‑pass filter?
τ = R × C
τ = R / C
τ = C / R
τ = 1 / (R × C)
Explanation - The time constant determines the filter’s response time.
Correct answer is: τ = R × C
Q.130 A 'bridge circuit' in a power supply uses which type of component to rectify AC?
Resistors
Capacitors
Diodes
Inductors
Explanation - Bridge rectifiers consist of four diodes.
Correct answer is: Diodes
Q.131 In a DC-DC buck converter, the output voltage is:
Higher than the input voltage
Lower than the input voltage
Equal to the input voltage
Variable irrespective of input
Explanation - Buck converters step voltage down.
Correct answer is: Lower than the input voltage
Q.132 In a DC-DC boost converter, the output voltage is:
Higher than the input voltage
Lower than the input voltage
Equal to the input voltage
Always equal to 12V
Explanation - Boost converters step voltage up.
Correct answer is: Higher than the input voltage
Q.133 The 'efficiency' of a power converter is calculated as:
Output power / input power
Input power / output power
Output current / input current
Input voltage / output voltage
Explanation - Efficiency is the ratio of output to input power, usually expressed as a percentage.
Correct answer is: Output power / input power
Q.134 In a transformer, if the core material has high magnetic permeability, what is the effect on the transformer's operation?
Reduced core losses
Increased core losses
Higher voltage output
Lower voltage output
Explanation - High permeability reduces hysteresis and eddy current losses.
Correct answer is: Reduced core losses
Q.135 Which of the following is the best method to reduce the ripple voltage in a power supply?
Add more series resistors
Add a larger capacitor
Increase the transformer turns ratio
Use a diode with higher forward voltage
Explanation - A larger capacitance reduces ripple by storing more charge.
Correct answer is: Add a larger capacitor
Q.136 A 'flyback' converter is used primarily in:
DC-DC buck applications
DC-DC boost applications
DC-DC isolated power supplies
AC power conditioning
Explanation - Flyback converters provide isolation between input and output.
Correct answer is: DC-DC isolated power supplies
Q.137 Which parameter of a transformer determines its ability to handle high currents?
Turns ratio
Core size and material
Primary voltage rating
Number of secondary coils
Explanation - A larger core can accommodate higher flux and current.
Correct answer is: Core size and material
Q.138 The 'magnetic flux density' (B) inside a transformer core is directly proportional to:
Turns number
Core area
Primary current
All of the above
Explanation - B = μ₀μₙNI/A, proportional to N, I, and inversely to A.
Correct answer is: All of the above
Q.139 The 'core loss' in a transformer is mainly due to:
Resistive heating in windings
Hysteresis and eddy currents
Mechanical vibrations
Capacitive coupling
Explanation - Core loss arises from magnetization cycles and induced currents.
Correct answer is: Hysteresis and eddy currents
Q.140 In an AC circuit, the 'power factor' of a purely inductive load is:
Zero
One
Negative one
Negative zero
Explanation - Inductive loads have current lagging voltage by 90°, making power factor zero.
Correct answer is: Zero
Q.141 The 'resonant frequency' of an LC circuit in a radio receiver determines:
The bandwidth
The center frequency
The power output
The noise figure
Explanation - Resonant frequency selects the tuned frequency in a receiver.
Correct answer is: The center frequency
Q.142 Which of the following best describes the 'stability' of a power supply?
Its ability to maintain constant output under load variations
Its ability to provide maximum voltage
Its ability to operate at high frequency
Its ability to step voltage up
Explanation - Stability refers to output constancy despite load changes.
Correct answer is: Its ability to maintain constant output under load variations
Q.143 The 'regulation' of a power supply is defined as:
The change in output voltage with input voltage variation
The change in output current with load variation
The output voltage divided by input voltage
The output current divided by input current
Explanation - Regulation measures output voltage stability versus input changes.
Correct answer is: The change in output voltage with input voltage variation
Q.144 In a DC-DC converter, the 'dead‑time' is the period during which:
Both switches are on
Both switches are off
Only one switch is on
Only one switch is off
Explanation - Dead‑time prevents shoot‑through by ensuring both switches are off briefly.
Correct answer is: Both switches are off
Q.145 Which device is commonly used to protect a transformer from over‑temperature conditions?
Fuse
Thermistor
Thermocouple
Temperature sensor with relay
Explanation - A thermistor can sense temperature rise and trigger a protective action.
Correct answer is: Thermistor
Q.146 Which type of AC circuit is used in induction heating?
Resistive load only
Inductive load only
Capacitive load only
Combined resistive‑inductive load
Explanation - Induction heating relies on high‑frequency inductive loads.
Correct answer is: Inductive load only
Q.147 In an RF circuit, the 'Q factor' of a resonant tank is:
Ratio of resonant frequency to bandwidth
Ratio of resistance to inductance
Ratio of inductance to capacitance
Ratio of current to voltage
Explanation - Q = f_res / BW indicates selectivity of the resonant circuit.
Correct answer is: Ratio of resonant frequency to bandwidth
Q.148 Which of the following is a key parameter for a microcontroller’s input stage?
Input impedance
Output power
Core voltage
Clock frequency
Explanation - High input impedance minimizes loading on the signal source.
Correct answer is: Input impedance
Q.149 Which of the following statements about a 'copper wire' used as a conductor is TRUE?
It has infinite conductivity
Its resistance increases with frequency
It is a good conductor of electricity
It stores electrical energy
Explanation - Copper has high conductivity and low resistance.
Correct answer is: It is a good conductor of electricity
Q.150 Which of the following is NOT a common method for reducing electromagnetic interference (EMI) in a circuit?
Use of shielded cables
Adding bypass capacitors
Increasing component spacing
Using a high‑gain amplifier
Explanation - High‑gain amplifiers can actually increase EMI; shielding and decoupling help reduce it.
Correct answer is: Using a high‑gain amplifier
Q.151 In a digital integrated circuit, the 'logic threshold' is:
The minimum voltage for operation
The voltage at which a logic level changes
The maximum voltage the circuit can handle
The average voltage in idle state
Explanation - Logic threshold distinguishes between logic '0' and '1'.
Correct answer is: The voltage at which a logic level changes
Q.152 The 'load line' in a transistor’s output characteristic represents:
The range of permissible output currents
The relationship between collector current and collector‑emitter voltage under a given load
The maximum collector current the transistor can handle
The relationship between base current and collector voltage
Explanation - Load line shows operating point for a given external load.
Correct answer is: The relationship between collector current and collector‑emitter voltage under a given load
Q.153 Which of the following is a key benefit of using a 'switch‑mode power supply' (SMPS) over a linear regulator?
Higher efficiency
Lower cost
Higher noise
Simpler design
Explanation - SMPS achieves higher efficiency by switching rather than dissipating excess power.
Correct answer is: Higher efficiency
Q.154 In high‑speed digital circuits, 'signal integrity' issues are mainly caused by:
Resistor tolerances
Parasitic capacitances and inductances
Switching speed of transistors
Ambient temperature
Explanation - Parasitics lead to reflections, ringing, and crosstalk.
Correct answer is: Parasitic capacitances and inductances
Q.155 Which of the following is a typical application of a 'linear regulator'?
High‑power power supplies
Low‑voltage, low‑noise power for analog circuits
Digital signal processing
Wireless power transfer
Explanation - Linear regulators provide clean, stable voltages for sensitive analog parts.
Correct answer is: Low‑voltage, low‑noise power for analog circuits
Q.156 Which of the following best defines the term 'noise figure' in an amplifier?
The ratio of input to output voltage
The increase in noise power due to the amplifier
The maximum gain of the amplifier
The bandwidth of the amplifier
Explanation - Noise figure measures how much an amplifier adds noise to the input signal.
Correct answer is: The increase in noise power due to the amplifier