Q.1 What is the primary purpose of a transformer in a high‑voltage generator?
To convert AC to DC
To increase or decrease voltage levels
To measure current
To store energy
Explanation - A transformer steps up the generated low voltage to a high voltage for transmission, or steps it down for distribution.
Correct answer is: To increase or decrease voltage levels
Q.2 Which of the following is NOT a typical method of generating high voltages?
Induction coils
Static generators (Van de Graaff)
Electrostatic precipitators
Pulse‑width modulation circuits
Explanation - Electrostatic precipitators use high voltage to charge particles for removal, but they do not generate high voltages themselves.
Correct answer is: Electrostatic precipitators
Q.3 In a Van de Graaff generator, what material is typically used for the moving belt?
Conductive metal
Non‑conductive rubber
Semiconductor silicon
Graphite block
Explanation - A non‑conductive belt carries charge to the high‑voltage terminal without allowing it to leak back to the base.
Correct answer is: Non‑conductive rubber
Q.4 Which phenomenon limits the maximum attainable voltage in a dielectric medium?
Capacitance
Breakdown
Resonance
Inductance
Explanation - Electrical breakdown occurs when the electric field exceeds the dielectric strength, causing a sudden increase in conductivity.
Correct answer is: Breakdown
Q.5 A Tesla coil primarily uses which type of resonance to achieve high voltage?
Mechanical resonance
Electrical resonance
Acoustic resonance
Magnetic resonance
Explanation - A Tesla coil is a tuned circuit that resonates at a high frequency, creating a large voltage difference between primary and secondary windings.
Correct answer is: Electrical resonance
Q.6 What is the typical operating frequency of a high‑voltage laboratory transformer?
50 Hz
60 Hz
400 Hz
10 kHz
Explanation - High‑voltage generators for experiments often operate at 400 Hz to reduce core size and improve efficiency.
Correct answer is: 400 Hz
Q.7 Which component is used to smooth the output of a high‑voltage rectifier?
Inductor
Capacitor
Resistor
Diode bridge
Explanation - A capacitor filters ripple in the rectified output, providing a more constant DC high voltage.
Correct answer is: Capacitor
Q.8 In high‑voltage pulsed power systems, what is the purpose of a crowbar circuit?
To regulate voltage
To provide surge protection
To store charge
To increase current
Explanation - A crowbar instantly shorts the output when over‑voltage occurs, protecting sensitive components.
Correct answer is: To provide surge protection
Q.9 Which of the following is a major safety hazard when working with high voltage?
Thermal expansion
Acoustic noise
Arc flash
Magnetic fields
Explanation - Arc flash can release intense heat and light, posing serious injury risks.
Correct answer is: Arc flash
Q.10 What is the typical dielectric strength of air at STP?
30 kV/mm
3 kV/mm
0.3 kV/mm
30 MV/mm
Explanation - Air breaks down at approximately 3 kV per millimeter of gap.
Correct answer is: 3 kV/mm
Q.11 A high‑voltage generator often uses which type of winding to reduce copper losses?
Solid copper wire
Litz wire
Aluminum foil
Stainless steel wire
Explanation - Litz wire comprises many small strands, reducing skin effect losses at high frequencies.
Correct answer is: Litz wire
Q.12 Which parameter describes how much voltage can be stored in a capacitor?
Resistance
Capacitance
Inductance
Impedance
Explanation - Capacitance determines the charge a capacitor can hold for a given voltage.
Correct answer is: Capacitance
Q.13 What is the role of a flyback transformer in a high‑voltage pulser?
To store magnetic energy
To step up voltage
To regulate current
To filter noise
Explanation - A flyback transformer stores energy during the on‑phase and releases it during the off‑phase, producing high‑voltage pulses.
Correct answer is: To store magnetic energy
Q.14 Which safety device is essential when handling high‑voltage equipment?
Thermometer
Ground fault circuit interrupter (GFCI)
Multimeter
Oscilloscope
Explanation - GFCI detects leakage currents and trips the circuit to prevent electric shock.
Correct answer is: Ground fault circuit interrupter (GFCI)
Q.15 The term 'HVDC' stands for:
High Voltage Direct Current
High Voltage Digital Converter
High Variable DC
High Voltage DC Distribution
Explanation - HVDC refers to the transmission of electric power using high‑voltage DC lines.
Correct answer is: High Voltage Direct Current
Q.16 In a high‑voltage DC source, what is the primary advantage over AC for long‑distance transmission?
Lower skin effect
Higher reactive losses
Simpler transformers
Higher capacitive losses
Explanation - DC eliminates skin effect and reactive losses, allowing more efficient long‑distance transmission.
Correct answer is: Lower skin effect
Q.17 Which of the following materials is commonly used as a dielectric in high‑voltage capacitors?
Paper
Ceramic
Glass
All of the above
Explanation - Paper, ceramic, and glass are all used as dielectric media in different capacitor types.
Correct answer is: All of the above
Q.18 What does 'arc suppression' mean in high‑voltage circuits?
Increasing arc length
Reducing arc intensity
Preventing arc formation
Amplifying arc voltage
Explanation - Arc suppression techniques aim to stop arcs from initiating or propagating.
Correct answer is: Preventing arc formation
Q.19 In a high‑voltage pulsed power system, what is the purpose of a pulse‑forming line?
To shape the pulse waveform
To increase voltage
To filter noise
To store energy
Explanation - Pulse‑forming lines create controlled rise/fall times and pulse duration.
Correct answer is: To shape the pulse waveform
Q.20 Which of the following best describes 'electrostatic induction' in a high‑voltage generator?
Transfer of charge via direct contact
Transfer of charge through a dielectric
Transfer of charge through a magnetic field
Transfer of charge via chemical reaction
Explanation - Induction involves charging a conductor by proximity to a charged object without contact.
Correct answer is: Transfer of charge through a dielectric
Q.21 What is the purpose of a voltage divider in a high‑voltage test circuit?
To measure current
To reduce voltage to a measurable level
To increase voltage
To filter noise
Explanation - A voltage divider scales down high voltage so that instruments can safely read the value.
Correct answer is: To reduce voltage to a measurable level
Q.22 Which of the following is a characteristic of a 'solid‑state' high‑voltage rectifier?
Mechanical contacts
No moving parts
High maintenance
High wear rate
Explanation - Solid‑state rectifiers use semiconductor devices, avoiding mechanical wear.
Correct answer is: No moving parts
Q.23 The 'skin effect' causes which of the following?
Current to concentrate near the center of the conductor
Current to concentrate near the surface of the conductor
Uniform current distribution
Reduced AC resistance
Explanation - At high frequencies, AC current flows primarily at the outer surface, increasing effective resistance.
Correct answer is: Current to concentrate near the surface of the conductor
Q.24 Which of the following is NOT a typical component of a high‑voltage power supply?
Inductor
Capacitor
Transformer
Resistor network
Explanation - Resistors are not commonly used for high‑voltage generation; they dissipate power as heat.
Correct answer is: Resistor network
Q.25 A high‑voltage spark gap is used primarily for:
Voltage measurement
Current regulation
Energy storage
Voltage limiting
Explanation - A spark gap conducts when voltage exceeds a threshold, protecting circuits from over‑voltage.
Correct answer is: Voltage limiting
Q.26 Which phenomenon allows a Van de Graaff generator to reach voltages of several megavolts?
Magnetic induction
Electrostatic induction
Capacitance increase
Thermal expansion
Explanation - The moving belt transfers charge to the terminal via induction, building up high voltage.
Correct answer is: Electrostatic induction
Q.27 What type of switch is often used to connect a high‑voltage circuit to a power source while ensuring safety?
Mechanical toggle
Solid‑state relay
Thermal overload
Fuse
Explanation - Solid‑state relays can isolate high‑voltage circuits with minimal contact wear.
Correct answer is: Solid‑state relay
Q.28 Which component is critical for preventing over‑current in a high‑voltage supply?
Fuse
Capacitor
Transformer
Inductor
Explanation - Fuses interrupt excessive current, protecting devices from damage.
Correct answer is: Fuse
Q.29 What does 'dielectric breakdown' refer to?
The insulating material becoming more resistant
The insulating material becoming conductive
The increase in capacitance
The decrease in capacitance
Explanation - Breakdown occurs when the material’s resistance drops dramatically, allowing current flow.
Correct answer is: The insulating material becoming conductive
Q.30 Which of the following is a key advantage of a Tesla coil?
High current output
Low frequency operation
High voltage with no direct connection to mains
Stable DC output
Explanation - Tesla coils generate high voltage through resonant AC, independent of the mains source.
Correct answer is: High voltage with no direct connection to mains
Q.31 In a high‑voltage laboratory setting, what is the primary purpose of a Faraday cage?
To generate high voltage
To contain electromagnetic fields
To step up voltage
To measure voltage
Explanation - A Faraday cage shields interior from external electric fields, protecting equipment and personnel.
Correct answer is: To contain electromagnetic fields
Q.32 Which of the following best describes 'high‑frequency leakage'?
Signal loss over long distances
Current flow through unintended paths
Increase in voltage
Decrease in capacitance
Explanation - Leakage current occurs when high‑frequency energy escapes the intended circuit, often through insulation.
Correct answer is: Current flow through unintended paths
Q.33 What is the main function of a ballast in a high‑voltage discharge tube?
Maintain constant voltage
Limit current
Increase capacitance
Reduce magnetic field
Explanation - A ballast restricts current flow, preventing runaway discharge.
Correct answer is: Limit current
Q.34 Which type of transformer winding arrangement is most common in high‑voltage power supplies?
Series
Parallel
Star
Delta
Explanation - Star (Y) connection is preferred for high voltage due to reduced voltage stresses on individual windings.
Correct answer is: Star
Q.35 High‑voltage capacitors in power supplies are often constructed with what type of dielectric to handle high stresses?
Paper
Foil
Ceramic
All of the above
Explanation - Each dielectric offers different advantages for managing high voltage and temperature.
Correct answer is: All of the above
Q.36 Which component is used to convert high‑voltage DC to AC for transmission?
Inverter
Rectifier
Transformer
Capacitor bank
Explanation - An inverter converts DC to AC; the AC is then stepped up by a transformer for transmission.
Correct answer is: Inverter
Q.37 What does 'high‑voltage leakage current' primarily depend on?
Dielectric strength
Insulation thickness
Both A and B
Temperature only
Explanation - Leakage current is influenced by dielectric strength and the thickness of insulation.
Correct answer is: Both A and B
Q.38 In a high‑voltage generator, why is the use of a low‑resistance grounding system essential?
To minimize voltage drop
To prevent heating
To increase magnetic field
To reduce capacitance
Explanation - A low‑resistance ground ensures that excess charge quickly dissipates, preventing dangerous voltages.
Correct answer is: To minimize voltage drop
Q.39 What is the main advantage of using a high‑frequency transformer for high‑voltage generation?
Smaller size
Higher efficiency at low power
Lower cost
No magnetic field
Explanation - Higher frequency allows for smaller core size due to reduced magnetic flux requirements.
Correct answer is: Smaller size
Q.40 In a DC‑to‑DC converter, which topology is commonly used to generate high voltage from a low‑voltage input?
Buck
Boost
Buck‑boost
Cuk
Explanation - A boost converter steps up voltage, making it suitable for high‑voltage generation from a low‑voltage source.
Correct answer is: Boost
Q.41 What is the primary safety risk when operating a high‑voltage pulse generator?
Overheating
Arc flash
Short‑circuit
Mechanical failure
Explanation - Arc flash can produce intense light and heat, causing severe burns or equipment damage.
Correct answer is: Arc flash
Q.42 Which type of capacitor is known for its high voltage and low loss properties?
Ceramic
Tantalum
Supercapacitor
Film
Explanation - Film capacitors can handle high voltages with low dielectric losses and good reliability.
Correct answer is: Film
Q.43 Why are high‑frequency resonant circuits preferred for generating high voltage pulses?
Lower power consumption
Higher magnetic field
Simpler construction
Higher Q factor for energy transfer
Explanation - A high Q resonant circuit efficiently stores and releases energy, producing sharp voltage spikes.
Correct answer is: Higher Q factor for energy transfer
Q.44 What is a key design consideration for the insulation of a high‑voltage transformer?
Thermal conductivity
Mechanical strength
Electrical dielectric strength
Magnetic permeability
Explanation - The insulation must withstand the maximum voltage without breaking down.
Correct answer is: Electrical dielectric strength
Q.45 Which phenomenon is responsible for the 'flashover' along a surface?
Surface erosion
Corona discharge
Arc flash
Dielectric breakdown
Explanation - Corona discharge initiates along a surface when the electric field exceeds the breakdown threshold.
Correct answer is: Corona discharge
Q.46 In high‑voltage testing, what device is used to measure voltage without loading the circuit?
Voltmeter
Voltage divider
High‑voltage probe
Clamp meter
Explanation - A high‑voltage probe offers high impedance and isolation, preventing loading effects.
Correct answer is: High‑voltage probe
Q.47 Which material is often used as a dielectric for high‑temperature, high‑voltage capacitors?
Polyethylene
PTFE
Silicone
All of the above
Explanation - These polymers provide good dielectric strength and thermal stability.
Correct answer is: All of the above
Q.48 Which component is critical for ensuring that a high‑voltage system can be switched off quickly?
Fuse
Circuit breaker
Relay
All of the above
Explanation - Circuit breakers interrupt current flow rapidly, protecting against faults.
Correct answer is: Circuit breaker
Q.49 What is the main function of a 'bleeder resistor' in a high‑voltage system?
Limit current during operation
Provide a discharge path for stored charge
Increase voltage
Store energy
Explanation - Bleeder resistors safely discharge capacitors or other storage elements after power removal.
Correct answer is: Provide a discharge path for stored charge
Q.50 In high‑voltage power supplies, why is a 'snubber' circuit often included?
To absorb voltage spikes
To increase voltage
To filter noise
To reduce current
Explanation - Snubbers mitigate overshoot and ringing caused by inductive elements switching.
Correct answer is: To absorb voltage spikes
Q.51 Which type of discharge is typically used for high‑voltage calibration of sensors?
Spark gap
Glow discharge
Corona discharge
All of the above
Explanation - Different discharge types provide specific characteristics for calibration purposes.
Correct answer is: All of the above
Q.52 Which component is used to convert a high‑voltage DC into a low‑voltage AC for measurement?
Inverter
Rectifier
Transformer
Voltage regulator
Explanation - An inverter changes DC to AC; the AC can then be stepped down by a transformer for measurement.
Correct answer is: Inverter
Q.53 What is a 'dead zone' in the context of a high‑voltage controller?
The range of voltage where no control action occurs
A region of insulation failure
An area with no magnetic field
A period of low current
Explanation - Dead zones are intentional to prevent oscillations near the setpoint.
Correct answer is: The range of voltage where no control action occurs
Q.54 Which of the following is NOT a common type of high‑voltage switch?
Dry‑contact relay
Solid‑state relay
Mechanical contactor
Thermal overload switch
Explanation - Thermal overload switches are for current protection, not high‑voltage switching.
Correct answer is: Thermal overload switch
Q.55 In a high‑voltage test stand, what is the primary purpose of a 'surge protector'?
To limit over‑current
To clamp transient over‑voltage
To increase voltage
To store energy
Explanation - Surge protectors suppress fast over‑voltage spikes, safeguarding equipment.
Correct answer is: To clamp transient over‑voltage
Q.56 Which of the following best describes the 'voltage drop' across a high‑voltage cable?
Drop due to resistance
Drop due to inductance
Drop due to capacitance
All of the above
Explanation - Voltage drops result from resistance, inductive reactance, and capacitive effects.
Correct answer is: All of the above
Q.57 In high‑voltage AC transmission, what is the function of a 'static var compensator'?
To regulate voltage
To limit current
To step up voltage
To increase resistance
Explanation - Static var compensators adjust reactive power, stabilizing system voltage.
Correct answer is: To regulate voltage
Q.58 What is the main advantage of using a 'flyback' transformer in a high‑voltage pulse generator?
High current delivery
Energy storage during the pulse
Low frequency operation
Reduced magnetic losses
Explanation - The flyback stores magnetic energy when the switch is on, releasing it as a pulse when off.
Correct answer is: Energy storage during the pulse
Q.59 Which law explains why high‑voltage circuits must be isolated from ground?
Ohm’s Law
Kirchhoff’s Voltage Law
Faraday’s Law
Coulomb’s Law
Explanation - KVL requires that the sum of voltage drops around a closed loop is zero; isolation ensures proper reference.
Correct answer is: Kirchhoff’s Voltage Law
Q.60 A high‑voltage DC power supply typically uses which type of rectifier?
Half‑wave
Full‑wave
Bridge
Single‑phase
Explanation - A bridge rectifier provides full‑wave rectification, maximizing efficiency for DC output.
Correct answer is: Bridge
Q.61 In a high‑voltage experimental setup, why is a 'safety interlock' important?
To limit current
To shut off power when access is detected
To increase voltage
To prevent thermal overload
Explanation - Safety interlocks automatically disconnect power if a safety door is opened, protecting users.
Correct answer is: To shut off power when access is detected
Q.62 Which of the following is a characteristic of a 'solid‑state' high‑voltage inverter?
High efficiency
Mechanical wear
High electromagnetic noise
Low frequency output
Explanation - Solid‑state devices have low resistive losses and high switching speeds, enhancing efficiency.
Correct answer is: High efficiency
Q.63 What is the main purpose of a 'bleed resistor' in a high‑voltage system?
To dissipate heat
To provide a controlled discharge path
To increase voltage
To store energy
Explanation - Bleed resistors safely discharge stored high‑voltage energy after power is removed.
Correct answer is: To provide a controlled discharge path
Q.64 Which of the following describes 'magnetic flux density' in a high‑voltage transformer core?
Electric field intensity
Magnetic field per unit length
Magnetic field per unit area
Electric flux per unit area
Explanation - Flux density (B) is the magnetic flux per unit area of the core.
Correct answer is: Magnetic field per unit area
Q.65 A high‑voltage generator uses a 'resonant tank circuit' primarily to:
Store energy in a capacitor
Control current
Generate high voltage through resonance
Reduce temperature
Explanation - The tank circuit resonates at a set frequency, amplifying voltage swings.
Correct answer is: Generate high voltage through resonance
Q.66 Which phenomenon is responsible for 'corona discharge' along a high‑voltage wire?
Dielectric breakdown of air
Electric field exceeding ionization threshold
Magnetic field interaction
Resonance with the ground
Explanation - When the electric field is strong enough to ionize nearby gas, a corona forms.
Correct answer is: Electric field exceeding ionization threshold
Q.67 High‑voltage capacitors are often rated by their 'voltage rating'. What does this indicate?
Maximum safe operating voltage
Minimum operating voltage
Peak voltage during pulses
Average operating voltage
Explanation - The voltage rating is the maximum voltage the capacitor can handle without damage.
Correct answer is: Maximum safe operating voltage
Q.68 In a high‑voltage circuit, what is the main role of a 'snubber diode'?
To clamp reverse voltage
To store energy
To limit current
To increase voltage
Explanation - A snubber diode protects the switching device from reverse voltage spikes.
Correct answer is: To clamp reverse voltage
Q.69 Which component is commonly used to provide a 'hard‑off' in high‑voltage power supplies?
Relay
Solid‑state relay
Fuse
All of the above
Explanation - All listed devices can interrupt high‑voltage circuits, each with different characteristics.
Correct answer is: All of the above
Q.70 What does 'impedance matching' in a high‑voltage transmission line aim to achieve?
Maximum power transfer
Minimum voltage drop
Reduced reflections
All of the above
Explanation - Impedance matching ensures efficient power transfer and reduces voltage standing waves.
Correct answer is: All of the above
Q.71 The 'Faraday constant' is used in high‑voltage electrochemistry to calculate:
Capacitance
Charge transfer per mole of electrons
Voltage drop
Current density
Explanation - The Faraday constant represents the charge per mole of electrons, crucial in electrolysis calculations.
Correct answer is: Charge transfer per mole of electrons
Q.72 A high‑voltage generator often uses a 'feedback loop' for stability. What does this loop primarily control?
Voltage output
Current output
Temperature
Frequency
Explanation - Feedback stabilizes the output voltage by comparing it to a reference and adjusting accordingly.
Correct answer is: Voltage output
Q.73 What is the typical purpose of a 'high‑voltage ballast' in a fluorescent lamp circuit?
Limit current
Increase voltage
Store energy
Reduce magnetic field
Explanation - A ballast limits the current to safe levels after the lamp ignites.
Correct answer is: Limit current
Q.74 Which of the following is NOT a type of high‑voltage insulation?
Paper
Oil
Water
Silicone
Explanation - Water is a conductor, not an insulator, and cannot be used for high‑voltage insulation.
Correct answer is: Water
Q.75 In high‑voltage DC transmission, why is 'reactive power' considered less critical?
DC has no reactive power
Reactive power increases losses
Reactive power can be easily managed
Reactive power is always high
Explanation - DC circuits have no inductive or capacitive reactive components, so reactive power is irrelevant.
Correct answer is: DC has no reactive power
Q.76 Which device is used to measure high‑frequency voltage in a high‑voltage system?
Oscilloscope with high‑voltage probe
Multimeter
Thermometer
Calorimeter
Explanation - An oscilloscope with a suitable probe can capture high‑frequency voltage waveforms.
Correct answer is: Oscilloscope with high‑voltage probe
Q.77 What is a key advantage of using 'dry‑contact' relays for high‑voltage isolation?
No power consumption when off
High current handling
Low resistance
High voltage rating
Explanation - Dry‑contact relays use no external power for switching, making them safe for high‑voltage isolation.
Correct answer is: No power consumption when off
Q.78 In high‑voltage generation, what is the role of a 'magnetic core'?
To store electric energy
To increase magnetic flux
To reduce resistance
To generate electric fields
Explanation - The core guides magnetic flux, enabling efficient coupling between primary and secondary windings.
Correct answer is: To increase magnetic flux
Q.79 Which of the following is a common application for a high‑voltage generator in physics experiments?
Particle acceleration
Thermal imaging
Sound generation
Data storage
Explanation - High‑voltage generators are used to accelerate charged particles in accelerators.
Correct answer is: Particle acceleration
Q.80 What is the main factor that limits the size of a high‑voltage cable?
Insulation thickness
Magnetic field strength
Mechanical strength
All of the above
Explanation - Higher voltage requires thicker insulation, which increases cable size.
Correct answer is: Insulation thickness
Q.81 Why are high‑voltage pulse generators often used in medical imaging?
To create X‑rays
To generate sound waves
To deliver therapy
To produce light
Explanation - High‑voltage pulses accelerate electrons to generate X‑ray photons for imaging.
Correct answer is: To create X‑rays
Q.82 A high‑voltage DC power supply typically uses a 'voltage regulator'. What does it do?
Keeps voltage constant despite load changes
Increases voltage
Decreases current
Stores energy
Explanation - A regulator maintains a fixed output voltage regardless of load variations.
Correct answer is: Keeps voltage constant despite load changes
Q.83 What is the main difference between a 'half‑wave rectifier' and a 'full‑wave rectifier'?
Half‑wave rectifies only one side of the AC waveform
Full‑wave rectifies both sides of the AC waveform
Both A and B
None of the above
Explanation - Half‑wave uses one half of the waveform, full‑wave uses both halves for higher efficiency.
Correct answer is: Both A and B
Q.84 What is a 'high‑voltage spark gap' used for in a pulsed power system?
To limit current
To initiate a controlled discharge
To step up voltage
To filter noise
Explanation - A spark gap conducts when voltage exceeds a threshold, creating a controlled arc.
Correct answer is: To initiate a controlled discharge
Q.85 Which of the following best describes the 'Q factor' of a resonant circuit?
Quality of the circuit’s energy storage
Rate of energy loss
Resonant frequency
All of the above
Explanation - The Q factor indicates how efficiently a resonant circuit stores energy relative to losses.
Correct answer is: Quality of the circuit’s energy storage
Q.86 In a high‑voltage generator, what is the main purpose of a 'grounded return path'?
To provide a safe reference
To increase voltage
To store energy
To reduce current
Explanation - The return path connects to earth ground, providing a reference and safety for stray currents.
Correct answer is: To provide a safe reference
Q.87 What is the primary reason for using 'tantalum capacitors' in high‑voltage circuits?
High capacitance density
High voltage tolerance
Low cost
Low ESR
Explanation - Tantalum capacitors can handle high voltages with low leakage, making them suitable for HV circuits.
Correct answer is: High voltage tolerance
Q.88 Which of the following is a typical safety measure for handling high‑voltage AC sources?
Use of insulated gloves
Avoidance of conductive objects
Both A and B
None of the above
Explanation - Insulated gloves and avoiding conductive tools reduce the risk of shock.
Correct answer is: Both A and B
Q.89 In a high‑voltage transmission line, what is the purpose of a 'shunt reactor'?
To absorb reactive power
To step up voltage
To store energy
To reduce current
Explanation - A shunt reactor provides inductance to counter reactive power from capacitive line effects.
Correct answer is: To absorb reactive power
Q.90 A high‑voltage power supply uses a 'feedback resistor divider' to sense voltage. Why is this divider chosen?
To reduce voltage to measurable levels
To increase voltage
To filter noise
To limit current
Explanation - The divider steps down the high voltage so the feedback can be safely processed by electronics.
Correct answer is: To reduce voltage to measurable levels
Q.91 Which of the following is a characteristic of a 'soft‑switching' high‑voltage converter?
High efficiency
High EMI
High losses
Low frequency operation
Explanation - Soft‑switching reduces voltage spikes and switching losses, improving efficiency.
Correct answer is: High efficiency
Q.92 What does 'E-field intensity' refer to in a high‑voltage context?
Electric field magnitude per unit distance
Magnetic field magnitude per unit distance
Voltage per unit length
Current density
Explanation - E-field intensity is the electric field strength measured in volts per meter.
Correct answer is: Electric field magnitude per unit distance
Q.93 In high‑voltage pulsed systems, a 'delay line' is used for:
Adjusting pulse timing
Increasing voltage
Storing energy
Filtering noise
Explanation - Delay lines delay the arrival of a pulse, enabling precise timing control.
Correct answer is: Adjusting pulse timing
Q.94 Which of the following is a common method of protecting high‑voltage measurement equipment from over‑voltage?
Varistor
Thermistor
Resistor
Capacitor
Explanation - A varistor clamps the voltage to a safe level when it exceeds a threshold.
Correct answer is: Varistor
Q.95 What is the main purpose of a 'flyback transformer' in a high‑voltage power supply?
Store magnetic energy for a short pulse
Step down voltage
Reduce noise
Increase current
Explanation - The transformer stores energy when the switch is on and releases it during the off‑state.
Correct answer is: Store magnetic energy for a short pulse
Q.96 Which law explains how the voltage across a capacitor changes with charge?
Ohm's Law
Coulomb's Law
Capacitance Law
Gauss's Law
Explanation - V = Q/C relates the voltage across a capacitor to its stored charge and capacitance.
Correct answer is: Capacitance Law
Q.97 What does the term 'high‑frequency resonant converter' refer to?
A converter operating at low frequency
A converter that uses resonance at high frequency
A converter with no resonance
A converter that operates at DC
Explanation - It employs a resonant tank to achieve efficient energy transfer at high frequencies.
Correct answer is: A converter that uses resonance at high frequency
Q.98 Which of the following is a common type of 'high‑voltage power supply' used in X‑ray machines?
Switch‑mode
Linear
Resonant
All of the above
Explanation - X‑ray generators can use various topologies, each with specific advantages.
Correct answer is: All of the above
Q.99 In a high‑voltage circuit, why is it important to maintain a 'high clearance' between conductors?
To reduce electromagnetic interference
To prevent corona and breakdown
To increase current capacity
To lower capacitance
Explanation - Higher clearance reduces the electric field intensity, minimizing corona discharge and dielectric breakdown.
Correct answer is: To prevent corona and breakdown
Q.100 A high‑voltage generator often uses a 'power MOSFET' for switching. What advantage does a MOSFET provide?
High on‑resistance
Fast switching
High voltage rating
Low cost
Explanation - MOSFETs switch quickly, reducing switching losses in high‑voltage systems.
Correct answer is: Fast switching
Q.101 Which of the following is NOT a typical characteristic of a 'high‑voltage capacitor bank'?
High series resistance
Low equivalent series inductance
High dielectric absorption
High voltage rating
Explanation - Capacitor banks are designed to have low series resistance to minimize losses.
Correct answer is: High series resistance
Q.102 What is a 'quenching circuit' in a high‑voltage spark discharge system used for?
To maintain the spark
To extinguish the spark rapidly
To increase current
To step up voltage
Explanation - The quenching circuit stops the arc quickly, protecting components and ensuring safety.
Correct answer is: To extinguish the spark rapidly
Q.103 In a high‑voltage laboratory, why is a 'Faraday cage' used around a generator?
To generate high voltage
To protect from external fields
To store charge
To increase magnetic field
Explanation - A Faraday cage blocks external electric fields, protecting equipment and operators.
Correct answer is: To protect from external fields
Q.104 Which of the following is a common use for a high‑voltage pulse generator?
Medical imaging
Audio amplification
Data storage
Lighting
Explanation - High‑voltage pulses generate X‑rays used in diagnostic imaging.
Correct answer is: Medical imaging
Q.105 What does the term 'over‑voltage protection' refer to in a high‑voltage system?
Protection against low voltage
Protection against excessive voltage
Protection against current surges
Protection against temperature rise
Explanation - Over‑voltage protection devices prevent damage by clamping or interrupting high voltage transients.
Correct answer is: Protection against excessive voltage
Q.106 In high‑voltage power distribution, what is the purpose of a 'shunt capacitor'?
To store energy
To increase voltage
To absorb reactive power
To reduce current
Explanation - Shunt capacitors provide reactive power compensation, improving power factor.
Correct answer is: To absorb reactive power
Q.107 Which of the following best describes the 'Q factor' of a transformer?
Efficiency
Resonant bandwidth
Quality factor indicating energy stored versus lost
Turns ratio
Explanation - Q factor quantifies how well a transformer stores energy relative to its losses.
Correct answer is: Quality factor indicating energy stored versus lost
Q.108 In a high‑voltage test setup, what is the function of a 'current probe'?
Measure voltage
Measure current non‑invasively
Store energy
Regulate voltage
Explanation - A current probe measures current without interrupting the circuit, essential for HV systems.
Correct answer is: Measure current non‑invasively
Q.109 Which phenomenon is responsible for the 'flashover' along a high‑voltage cable?
Thermal runaway
Corona discharge
Dielectric breakdown
Electrostatic attraction
Explanation - Flashover occurs when the insulation between conductors fails, allowing current to jump the gap.
Correct answer is: Dielectric breakdown
Q.110 In a high‑voltage DC system, what does 'cable impedance' mainly determine?
Voltage rise
Voltage drop
Current capacity
All of the above
Explanation - Cable impedance affects voltage drop, rise, and current carrying ability.
Correct answer is: All of the above
Q.111 What is the main advantage of using 'polymer dielectric' capacitors in high‑voltage applications?
High temperature tolerance
Low cost
High capacitance
High leakage
Explanation - Polymer dielectrics maintain performance at elevated temperatures, suitable for HV systems.
Correct answer is: High temperature tolerance
Q.112 Which of the following is a typical safety recommendation for high‑voltage labs?
Wear non‑conductive shoes
Keep equipment dry
Both A and B
Use metal tools for better heat dissipation
Explanation - Non‑conductive footwear and dry conditions reduce shock risk.
Correct answer is: Both A and B
Q.113 What is a 'high‑voltage switch‑mode power supply' known for?
High efficiency
Large size
Low frequency operation
High cost
Explanation - Switch‑mode supplies use rapid switching to achieve high efficiency and compact size.
Correct answer is: High efficiency
Q.114 Which component is typically used to provide a 'hard‑off' in a high‑voltage system?
Relay
Fuse
Circuit breaker
All of the above
Explanation - All listed devices can interrupt power in a high‑voltage circuit.
Correct answer is: All of the above
Q.115 In high‑voltage applications, why is a 'low‑leakage' capacitor preferred?
To reduce power loss
To increase voltage rating
To lower cost
To increase current handling
Explanation - Low leakage reduces continuous power dissipation, important in high‑voltage circuits.
Correct answer is: To reduce power loss
Q.116 What is the typical voltage rating for a 100 µF high‑voltage capacitor used in a pulse generator?
100 V
500 V
2 kV
10 kV
Explanation - Pulse generators often require capacitors rated for several kilovolts to handle peak energies.
Correct answer is: 10 kV
Q.117 Which of the following is a key factor influencing the design of a high‑voltage cable?
Dielectric strength
Mechanical flexibility
Insulation thickness
All of the above
Explanation - All listed factors are critical for ensuring safe and reliable HV cable operation.
Correct answer is: All of the above
Q.118 In high‑voltage pulse generators, what is the role of a 'delay line'?
Store energy
Adjust timing of pulse
Increase voltage
Reduce current
Explanation - Delay lines are used to precisely time the arrival of high‑voltage pulses.
Correct answer is: Adjust timing of pulse
Q.119 What is the purpose of a 'voltage regulator' in a high‑voltage power supply?
Maintain constant voltage
Increase voltage
Limit current
Store energy
Explanation - A voltage regulator keeps the output voltage stable despite load changes.
Correct answer is: Maintain constant voltage
Q.120 Which of the following best describes the function of a 'flyback transformer' in a pulsed power system?
Store magnetic energy for a short pulse
Step down voltage
Filter noise
Increase current
Explanation - The transformer stores energy when the switch is on and releases it during the off‑state.
Correct answer is: Store magnetic energy for a short pulse
Q.121 Which phenomenon is responsible for 'corona discharge' along a high‑voltage wire?
Dielectric breakdown of air
Electric field exceeding ionization threshold
Magnetic field interaction
Resonance with ground
Explanation - When the field ionizes the surrounding air, a corona forms.
Correct answer is: Electric field exceeding ionization threshold
Q.122 What is a key advantage of using 'Litz wire' in high‑frequency transformers?
Reduced skin effect losses
Higher mechanical strength
Lower cost
Simpler construction
Explanation - Litz wire minimizes AC losses due to skin effect at high frequencies.
Correct answer is: Reduced skin effect losses
Q.123 In high‑voltage AC transmission, what is a 'shunt reactor' used for?
Absorb reactive power
Step up voltage
Store energy
Reduce current
Explanation - Shunt reactors counteract capacitive reactive power in long transmission lines.
Correct answer is: Absorb reactive power
Q.124 Which of the following is a typical method to reduce corona discharge in HV conductors?
Increase conductor diameter
Use thicker insulation
Add surface coatings
All of the above
Explanation - Larger diameter, thicker insulation, and coatings reduce surface electric fields.
Correct answer is: All of the above
Q.125 What is the primary function of a 'grounding rod' in a high‑voltage setup?
Provide a reference point
Increase voltage
Store energy
Reduce current
Explanation - It connects the system to earth, ensuring a safe reference for stray currents.
Correct answer is: Provide a reference point
Q.126 Which component is used to step up voltage in a high‑voltage generator?
Transformer
Rectifier
Capacitor
Resistor
Explanation - Transformers increase voltage levels via magnetic coupling.
Correct answer is: Transformer
Q.127 What does the term 'dielectric absorption' refer to in high‑voltage capacitors?
The ability to absorb dielectric materials
The tendency to slowly regain voltage after discharge
The ability to store energy in a magnetic field
The resistance to current flow
Explanation - Dielectric absorption causes a capacitor to slowly recover part of its charge after being discharged.
Correct answer is: The tendency to slowly regain voltage after discharge
Q.128 In a high‑voltage laboratory, why is a 'Faraday cage' used?
To generate high voltage
To block external electric fields
To store energy
To increase magnetic field
Explanation - A Faraday cage shields the interior from external electric fields and protects equipment.
Correct answer is: To block external electric fields
Q.129 Which of the following is a typical safety precaution when working with high‑voltage AC?
Wear insulated gloves
Keep wet tools near the circuit
Use metal shovels for grounding
All of the above
Explanation - Insulated gloves protect against accidental shocks; wet tools and metal shovels increase risk.
Correct answer is: Wear insulated gloves
Q.130 What is the main purpose of a 'bleeder resistor' in a high‑voltage system?
To store energy
To dissipate heat
To provide a controlled discharge path
To increase voltage
Explanation - It safely discharges stored energy after power is removed.
Correct answer is: To provide a controlled discharge path
Q.131 In a high‑voltage DC system, what does 'cable impedance' mainly determine?
Voltage drop
Current capacity
Both A and B
None of the above
Explanation - Cable impedance affects voltage drop and current handling.
Correct answer is: Both A and B
Q.132 Which of the following is an advantage of using a 'high‑voltage pulse generator' over a continuous HV supply?
Reduced thermal load
Continuous operation
Lower cost
Simpler design
Explanation - Pulsed operation concentrates energy in short bursts, limiting continuous heating.
Correct answer is: Reduced thermal load
Q.133 What is a common method to mitigate 'arc flash' in high‑voltage equipment?
Use of arc‑resistant gloves
Implementation of proper grounding
Adding a spark gap
All of the above
Explanation - Proper safety gear, grounding, and spark gaps all reduce arc flash hazards.
Correct answer is: All of the above
Q.134 Which component is critical for converting high‑voltage DC to AC for transmission?
Inverter
Rectifier
Transformer
Capacitor bank
Explanation - Inverters convert DC to AC; transformers then step up the voltage for transmission.
Correct answer is: Inverter
Q.135 What is the main function of a 'high‑voltage relay' in a control system?
To physically separate circuits
To step up voltage
To store energy
To measure voltage
Explanation - A relay uses a low‑current signal to open or close a high‑voltage circuit.
Correct answer is: To physically separate circuits
Q.136 Which of the following is NOT a characteristic of a high‑voltage DC power supply?
Low output noise
High efficiency
High voltage ripple
Precise voltage regulation
Explanation - High‑voltage DC supplies aim for low ripple to maintain stable operation.
Correct answer is: High voltage ripple
Q.137 In a high‑voltage laboratory, a 'current clamp meter' is used for what purpose?
Measure voltage
Measure current non‑invasively
Store energy
Regulate voltage
Explanation - The clamp measures current without breaking the circuit, essential for high‑voltage safety.
Correct answer is: Measure current non‑invasively
Q.138 Which of the following is a typical use for a 'high‑voltage spark gap' in pulsed power systems?
To initiate a controlled discharge
To regulate current
To step up voltage
To filter noise
Explanation - When voltage exceeds the gap threshold, a spark forms, initiating the discharge.
Correct answer is: To initiate a controlled discharge
Q.139 What is the main reason for using 'high‑frequency resonant converters' in high‑voltage generators?
Higher efficiency
Lower size
Both A and B
None of the above
Explanation - Resonant converters reduce losses and allow smaller components, improving efficiency.
Correct answer is: Both A and B
Q.140 Which of the following is a safety device used to detect and disconnect over‑voltage in a high‑voltage system?
Fuse
Circuit breaker
Voltage‑sensing relay
All of the above
Explanation - Voltage‑sensing relays monitor voltage and disconnect the circuit if it exceeds limits.
Correct answer is: Voltage‑sensing relay
Q.141 In a high‑voltage laboratory, which component is used to safely store and discharge energy for experiments?
Capacitor bank
Resistor network
Inductor coil
Transformer core
Explanation - Capacitor banks store large amounts of energy and can be discharged rapidly for testing.
Correct answer is: Capacitor bank
Q.142 What is the purpose of a 'voltage divider' in a high‑voltage measurement circuit?
To increase voltage
To reduce voltage to measurable levels
To filter noise
To limit current
Explanation - A divider scales down the high voltage for safe measurement by instruments.
Correct answer is: To reduce voltage to measurable levels
Q.143 Which of the following is NOT a common method of measuring high‑voltage AC?
Voltage probe
Voltage multiplier
High‑voltage transformer
Direct meter readout
Explanation - Direct meter readout on a high‑voltage source can damage the meter; a probe is required.
Correct answer is: Direct meter readout