Q.1 What type of instrument is used to measure electrical current by deflection of a needle in a magnetic field?
Voltmeter
Ammeter
Oscilloscope
Thermocouple
Explanation - An ammeter is designed to measure current. It uses a coil in a magnetic field; the current causes a torque that deflects a needle proportionally to current.
Correct answer is: Ammeter
Q.2 Which of the following instruments is most suitable for measuring very low voltages?
High‑resistance voltmeter
Low‑resistance voltmeter
Ammeter
Manometer
Explanation - A high‑resistance voltmeter has a high input impedance, minimizing voltage drop across the measuring circuit, making it ideal for low voltage measurement.
Correct answer is: High‑resistance voltmeter
Q.3 In a moving‑coil meter, the coil is usually made of:
Aluminium wire
Copper wire
Nickel‑tin alloy wire
Steel wire
Explanation - Copper is commonly used due to its low resistance and good conductivity, which reduces energy losses in moving‑coil meters.
Correct answer is: Copper wire
Q.4 The principle behind a D’Arsonval galvanometer is:
Electromagnetic induction
Magnetic attraction of iron core
Electrical resistance change
Capacitive coupling
Explanation - A D’Arsonval galvanometer operates on the principle that current through a coil in a magnetic field produces a torque that causes needle deflection.
Correct answer is: Electromagnetic induction
Q.5 Which instrument is primarily used to record variations of a physical quantity over time?
Analog meter
Digital multimeter
Chart recorder
Oscilloscope
Explanation - A chart recorder captures changes in a physical quantity by tracing a stylus on a moving paper, allowing long‑term recording.
Correct answer is: Chart recorder
Q.6 A manometer used to measure gas pressure typically consists of:
A liquid column
An electric coil
A glass tube and liquid
A digital display
Explanation - A manometer measures pressure by balancing a liquid column in a glass tube, where pressure difference causes liquid displacement.
Correct answer is: A glass tube and liquid
Q.7 What is the main disadvantage of using a mercury manometer?
High cost
Mercury toxicity
Low sensitivity
Large size
Explanation - Mercury is toxic and hazardous; disposal and leakage are major safety concerns, making mercury manometers less preferred.
Correct answer is: Mercury toxicity
Q.8 A moving‑iron meter is best suited for measuring:
Small currents
Large voltages
Low frequencies
High temperatures
Explanation - Moving‑iron meters have a soft‑iron core that responds to high voltages, making them suitable for such measurements.
Correct answer is: Large voltages
Q.9 Which of the following instruments converts mechanical displacement into an electrical signal?
Thermocouple
Potentiometer
Strain gauge
Oscilloscope
Explanation - A strain gauge changes resistance with mechanical strain, producing an electrical signal proportional to displacement.
Correct answer is: Strain gauge
Q.10 In a typical analog voltmeter, the scale is calibrated in:
Ohms
Volts
Amps
Farads
Explanation - Analog voltmeters are calibrated to display voltage directly on the scale.
Correct answer is: Volts
Q.11 Which instrument would you use to measure the frequency of an AC signal?
Ammeter
Voltmeter
Frequency counter
Thermocouple
Explanation - A frequency counter counts cycles per second, directly giving the signal’s frequency.
Correct answer is: Frequency counter
Q.12 Which component in a D’Arsonval galvanometer provides the restoring torque?
Magnet
Spring
Coil
Scale
Explanation - The spring provides a restoring torque that balances the magnetic torque, allowing needle deflection to be proportional to current.
Correct answer is: Spring
Q.13 What does a digital multimeter (DMM) measure?
Voltage, current, resistance
Temperature, pressure, humidity
Speed, distance, acceleration
Weight, volume, density
Explanation - A DMM is designed to measure the fundamental electrical parameters: voltage (V), current (A), and resistance (Ω).
Correct answer is: Voltage, current, resistance
Q.14 An indicator with a needle is known as:
An analog meter
A digital meter
A recording instrument
A transducer
Explanation - Analog meters display measurement on a moving needle over a scale.
Correct answer is: An analog meter
Q.15 Which instrument is commonly used to measure the pressure of gases at low pressure ranges?
Mercury manometer
Capacitance manometer
Torsion tube manometer
Differential pressure gauge
Explanation - Capacitance manometers are sensitive to low pressure variations, suitable for gases at low pressures.
Correct answer is: Capacitance manometer
Q.16 The sensitivity of a moving‑iron instrument depends on:
The core material
The coil resistance
The scale design
All of the above
Explanation - Sensitivity is influenced by the core’s magnetic properties, coil resistance, and how the scale is calibrated.
Correct answer is: All of the above
Q.17 Which of the following is a type of recording instrument that uses a magnetic tape to store data?
Chart recorder
Oscilloscope
Magnetic tape recorder
Galvanometer
Explanation - Magnetic tape recorders capture electrical signals onto magnetic tape for later playback.
Correct answer is: Magnetic tape recorder
Q.18 In instrumentation, the term 'transducer' refers to:
A device converting one form of energy into another
A scale of measurement
A power supply
An amplifier
Explanation - Transducers transform physical quantities (e.g., pressure, temperature) into electrical signals.
Correct answer is: A device converting one form of energy into another
Q.19 A strain gauge is often bonded to a:
Metallic surface
Plastic surface
Ceramic surface
All of the above
Explanation - Strain gauges are typically bonded to metal to measure deformation under mechanical load.
Correct answer is: Metallic surface
Q.20 Which component provides the reference voltage in a potentiometer used as a voltage divider?
Wiper
Fixed resistor
Variable resistor
Both wiper and fixed resistor
Explanation - The fixed resistor provides the full supply voltage; the wiper taps a fraction of this voltage.
Correct answer is: Fixed resistor
Q.21 The term 'linearity' in a meter refers to:
Uniform scale distribution
Proportional output over full range
Zero error
Full‑scale error
Explanation - Linearity indicates how closely the meter output follows a straight line across its range.
Correct answer is: Proportional output over full range
Q.22 Which of the following instruments is best for measuring very high voltage?
Voltmeter
High‑voltage probe
Ammeter
Thermocouple
Explanation - High‑voltage probes are designed to safely scale down high voltages for measurement.
Correct answer is: High‑voltage probe
Q.23 A 'null method' instrument is one that:
Uses a balance scale
Operates when the output is zero
Requires calibration with a known standard
Measures only AC quantities
Explanation - In a null method, the instrument is adjusted until its output reads zero, indicating a precise measurement.
Correct answer is: Operates when the output is zero
Q.24 Which of the following best describes a 'logarithmic amplifier'?
Amplifies signals linearly
Amplifies signals on a log scale
Provides a constant voltage output
Reduces noise
Explanation - A logarithmic amplifier compresses large dynamic ranges into smaller ones, useful in audio and signal processing.
Correct answer is: Amplifies signals on a log scale
Q.25 In a differential pressure gauge, the reading is:
The sum of two pressures
The difference between two pressures
Only one pressure
The average of two pressures
Explanation - Differential pressure gauges measure the pressure difference between two points.
Correct answer is: The difference between two pressures
Q.26 An 'auto‑zero' feature in a digital meter:
Automatically sets the zero point
Calibrates the meter to a standard reference
Removes temperature drift
Adjusts the display resolution
Explanation - Auto‑zero corrects for any offset in the meter’s measurement, ensuring accurate zero reading.
Correct answer is: Automatically sets the zero point
Q.27 Which of the following is a common error source in moving‑coil meters?
Core saturation
Magnetic flux leakage
Thermal drift
All of the above
Explanation - Moving‑coil meters can suffer from saturation, flux leakage, and thermal effects that affect accuracy.
Correct answer is: All of the above
Q.28 A 'logarithmic indicator' is commonly used in:
Sound level measurement
Temperature measurement
Voltage measurement
Current measurement
Explanation - Sound levels vary over a wide range; logarithmic scales (decibels) are suitable for display.
Correct answer is: Sound level measurement
Q.29 The 'zero error' in a voltmeter indicates:
A negative offset
An internal resistance mismatch
A scale error
All of the above
Explanation - Zero error means the meter reads a value other than zero when the input is zero, indicating a negative offset.
Correct answer is: A negative offset
Q.30 Which of the following instruments uses a 'capacitive' principle for measurement?
Capacitance manometer
Inductance meter
Galvanometer
Resistive thermometer
Explanation - Capacitance manometers measure pressure changes by detecting changes in capacitance.
Correct answer is: Capacitance manometer
Q.31 In instrumentation, the term 'sensitivity' refers to:
The range of measurement
The resolution of the instrument
The change in output per unit change in input
The error margin
Explanation - Sensitivity quantifies how much the instrument’s output changes for a small change in input.
Correct answer is: The change in output per unit change in input
Q.32 A 'moving‑iron' meter is best suited for measuring:
Very low currents
Medium currents
Very high currents
Only DC currents
Explanation - Moving‑iron meters are designed for high current ranges due to the soft‑iron core’s ability to handle large magnetic fields.
Correct answer is: Very high currents
Q.33 Which of the following is NOT a function of an instrument transformer?
Step‑down voltage
Current measurement
Voltage measurement
Temperature measurement
Explanation - Instrument transformers are used for voltage and current measurements, not for temperature.
Correct answer is: Temperature measurement
Q.34 A 'zero‑adjust' feature allows a user to:
Set the zero point to zero
Adjust the scale factor
Change the measurement range
Reset the instrument
Explanation - Zero‑adjust aligns the instrument’s zero output with the true zero measurement.
Correct answer is: Set the zero point to zero
Q.35 Which of these is an example of a digital indicator?
D'Arsonval galvanometer
Digital voltmeter
Mercury manometer
Moving coil meter
Explanation - Digital indicators display numeric readings on a digital screen.
Correct answer is: Digital voltmeter
Q.36 In a chart recorder, the 'stylus' is:
The moving needle
The pen that draws on paper
The power supply
The recording head
Explanation - The stylus traces a line on the recording paper, capturing the measured quantity.
Correct answer is: The pen that draws on paper
Q.37 Which of the following instruments typically uses a 'null method' for measurement?
D'Arsonval galvanometer
Digital voltmeter
Mercury manometer
Capacitive pressure sensor
Explanation - D'Arsonval galvanometers can be zeroed by adjusting the coil to produce zero deflection when no current flows.
Correct answer is: D'Arsonval galvanometer
Q.38 The term 'resolution' in a digital meter refers to:
The maximum reading
The smallest change it can display
The accuracy
The speed of reading
Explanation - Resolution indicates how fine the increments of measurement are in the digital display.
Correct answer is: The smallest change it can display
Q.39 A 'strain gauge' is often used in:
Pressure sensors
Temperature sensors
Position sensors
All of the above
Explanation - Strain gauges can be integrated into various sensors to measure deformation, pressure, or displacement.
Correct answer is: All of the above
Q.40 An 'instrumentation amplifier' is primarily used to:
Amplify high‑frequency signals
Amplify low‑level differential signals
Reduce noise only
Measure temperature
Explanation - Instrumentation amplifiers provide high input impedance and low output impedance, ideal for small differential signals.
Correct answer is: Amplify low‑level differential signals
Q.41 Which of the following instruments has the highest input impedance?
Ammeter
Voltmeter
Thermocouple
Digital multimeter
Explanation - Thermocouples present a very high input impedance, minimizing loading effects on the measured system.
Correct answer is: Thermocouple
Q.42 The 'full scale' of an analog meter indicates:
The maximum value it can display
The minimum value it can display
The error margin
The average reading
Explanation - Full scale is the upper limit of the meter’s measurement range.
Correct answer is: The maximum value it can display
Q.43 A 'torque transducer' converts:
Torque into electrical voltage
Voltage into current
Current into mechanical torque
Temperature into resistance
Explanation - Torque transducers generate an electrical signal proportional to the torque applied.
Correct answer is: Torque into electrical voltage
Q.44 Which of the following is a 'null method' instrument?
Ammeter
Capacitance manometer
D’Arsonval galvanometer
Digital voltmeter
Explanation - The D’Arsonval galvanometer uses a null method by setting the needle to zero when no current flows.
Correct answer is: D’Arsonval galvanometer
Q.45 In a moving‑coil meter, the 'coil resistance' must be kept:
Very high
Very low
Moderate
Irrelevant
Explanation - Low coil resistance reduces power dissipation and improves linearity in moving‑coil meters.
Correct answer is: Very low
Q.46 An 'electrostatic pendulum' is used to measure:
Electric potential
Magnetic field strength
Mechanical force
Temperature
Explanation - An electrostatic pendulum balances electrical forces to measure potential differences.
Correct answer is: Electric potential
Q.47 Which instrument is used for measuring the pressure drop across a filter?
Differential pressure gauge
Static manometer
Temperature gauge
Voltmeter
Explanation - Differential pressure gauges measure the difference in pressure before and after a filter.
Correct answer is: Differential pressure gauge
Q.48 A 'digital frequency counter' directly displays the:
Amplitude
Period
Frequency
Phase angle
Explanation - Frequency counters count cycles per second and display the frequency directly.
Correct answer is: Frequency
Q.49 The 'zero point' of a meter is:
The point where the reading is maximum
The point where the reading is zero
The point where the reading is negative
The point where the instrument is turned off
Explanation - The zero point indicates the instrument’s baseline, representing no input.
Correct answer is: The point where the reading is zero
Q.50 Which of the following is used to calibrate a digital multimeter?
A standard resistor
A known voltage source
Both a standard resistor and a known voltage source
None of the above
Explanation - Calibration often uses known resistances and voltages to verify accuracy.
Correct answer is: Both a standard resistor and a known voltage source
Q.51 A 'precision potentiometer' is often used as a:
Variable voltage source
Resistor divider
Temperature sensor
Current source
Explanation - Precision potentiometers provide fine voltage adjustments in precision circuits.
Correct answer is: Variable voltage source
Q.52 In a 'moving‑iron' instrument, the iron core is typically made of:
Steel
Aluminium
Copper
Iron‑silicon alloy
Explanation - Iron‑silicon alloys offer high magnetic permeability and low core losses.
Correct answer is: Iron‑silicon alloy
Q.53 The main disadvantage of a 'moving‑coil' meter compared to a 'moving‑iron' meter is:
Lower sensitivity
Higher cost
Limited range
All of the above
Explanation - Moving‑coil meters use precision components and are generally more expensive.
Correct answer is: Higher cost
Q.54 Which instrument measures temperature by the change in resistance of a metal?
Thermocouple
Resistance Temperature Detector (RTD)
Thermopile
Bimetallic thermometer
Explanation - RTDs use a metal element whose resistance varies predictably with temperature.
Correct answer is: Resistance Temperature Detector (RTD)
Q.55 Which of the following is used to measure humidity?
Barometer
Hygrometer
Thermometer
Anemometer
Explanation - Hygrometers are designed to determine the moisture content in air.
Correct answer is: Hygrometer
Q.56 An 'anemometer' is used to measure:
Wind speed
Pressure
Temperature
Humidity
Explanation - An anemometer measures the velocity of air or wind.
Correct answer is: Wind speed
Q.57 A 'photodiode' is commonly used for:
Detecting light intensity
Measuring temperature
Measuring pressure
Measuring sound level
Explanation - Photodiodes convert incident light into an electrical current proportional to intensity.
Correct answer is: Detecting light intensity
Q.58 Which of these instruments measures electric field intensity?
Electric field meter
Magnetic field meter
Voltage meter
Current meter
Explanation - Electric field meters measure the electric field strength in a given environment.
Correct answer is: Electric field meter
Q.59 An 'ultrasonic sensor' measures:
Sound intensity
Distance via sound waves
Temperature
Pressure
Explanation - Ultrasonic sensors use high‑frequency sound pulses to determine distance to an object.
Correct answer is: Distance via sound waves
Q.60 What is the function of a 'bridge circuit' in measurement?
To amplify signals
To balance unknown components
To convert AC to DC
To reduce noise
Explanation - Bridge circuits, like Wheatstone or Kelvin bridges, allow precise measurement by balancing known and unknown elements.
Correct answer is: To balance unknown components
Q.61 Which of the following is an example of an 'optical sensor'?
Photodiode
Strain gauge
Pressure transducer
Thermocouple
Explanation - Photodiodes detect optical (light) signals, making them optical sensors.
Correct answer is: Photodiode
Q.62 A 'capacitance pressure sensor' works on the principle of:
Resistance change
Capacitance variation
Voltage drop
Current increase
Explanation - Pressure changes alter the separation or area between plates, changing the capacitance.
Correct answer is: Capacitance variation
Q.63 Which instrument uses a 'pendulum' to measure gravitational acceleration?
Pendulum balance
Inertial sensor
Gyroscope
Accelerometer
Explanation - A pendulum balance measures weight by balancing a mass on a pendulum, revealing gravitational acceleration.
Correct answer is: Pendulum balance
Q.64 The 'output' of a strain gauge is typically:
Voltage
Current
Resistance
Both voltage and current
Explanation - Strain gauges change resistance when deformed, which is then measured by an electrical circuit.
Correct answer is: Resistance
Q.65 In a 'thermistor', the resistance:
Increases with temperature
Decreases with temperature
Remains constant
Depends on voltage
Explanation - NTC (negative temperature coefficient) thermistors see resistance drop as temperature rises.
Correct answer is: Decreases with temperature
Q.66 A 'magnetometer' measures:
Magnetic field strength
Electric field strength
Temperature
Pressure
Explanation - Magnetometers detect and quantify magnetic field intensity.
Correct answer is: Magnetic field strength
Q.67 Which type of instrument is best for measuring pulse rate?
Thermometer
Glucometer
Electrocardiograph (ECG)
Barometer
Explanation - An ECG records the electrical activity of the heart, providing pulse rate information.
Correct answer is: Electrocardiograph (ECG)
Q.68 A 'differential amplifier' is used to amplify:
Single‑ended signals
Differential signals
Both single‑ended and differential
None of the above
Explanation - Differential amplifiers amplify the voltage difference between two input terminals.
Correct answer is: Differential signals
Q.69 Which of the following is an example of a 'temperature‑to‑frequency' converter?
Thermocouple
Thermistor
PT100 sensor
Cold‑junction compensated RTD
Explanation - Some thermistors can be used with oscillators to output a frequency proportional to temperature.
Correct answer is: Thermistor
Q.70 The 'zero error' in a voltmeter is typically corrected by:
Adding a resistor
Using a zero‑adjust switch
Replacing the battery
Cleaning the probe
Explanation - Zero‑adjust switches set the instrument’s zero point by balancing internal offsets.
Correct answer is: Using a zero‑adjust switch
Q.71 In a 'bridge balance', the output is zero when:
All resistors are equal
The bridge is unbalanced
The input voltage is zero
The current is maximum
Explanation - A balanced bridge has equal ratios in both arms, producing no differential output.
Correct answer is: All resistors are equal
Q.72 Which instrument measures the 'electric potential difference' between two points?
Ammeter
Voltmeter
Current probe
Resistive thermometer
Explanation - Voltmeters measure the potential difference across two terminals.
Correct answer is: Voltmeter
Q.73 An 'electromagnetic flow meter' measures:
Mass flow rate
Pressure
Temperature
Velocity of conductive fluid
Explanation - It measures flow velocity by inducing voltage across a conductive fluid moving in a magnetic field.
Correct answer is: Velocity of conductive fluid
Q.74 A 'Kelvin bridge' is specifically used to measure:
Resistance of high‑value resistors
Temperature
Capacitance
Inductance
Explanation - The Kelvin bridge is designed for high‑precision resistance measurements with low error.
Correct answer is: Resistance of high‑value resistors
Q.75 Which of the following instruments uses a 'triangular waveform' for measurement?
Digital oscilloscope
Thermocouple
Voltmeter
Ammeter
Explanation - Oscilloscopes can use various waveforms, including triangular, for accurate time‑base scaling.
Correct answer is: Digital oscilloscope
Q.76 What is the main purpose of a 'null method' in measurement?
To zero the instrument
To amplify the signal
To reduce noise
To increase the measurement range
Explanation - Null method ensures the instrument reads zero when no quantity is present, enhancing accuracy.
Correct answer is: To zero the instrument
Q.77 In a 'capacitive sensor', the sensing element is:
Resistive
Capacitive
Inductive
Optical
Explanation - Capacitive sensors rely on changes in capacitance to detect a physical quantity.
Correct answer is: Capacitive
Q.78 Which of these instruments is best for measuring rapid changes in voltage?
Analog voltmeter
Digital voltmeter
Oscilloscope
Thermocouple
Explanation - Oscilloscopes can capture fast transient voltage changes on the screen.
Correct answer is: Oscilloscope
Q.79 A 'strain gauge' is commonly used in:
Weight scales
Temperature sensors
Pressure sensors
All of the above
Explanation - Strain gauges measure deformation, which can be linked to weight, pressure, or temperature.
Correct answer is: All of the above
Q.80 Which type of transducer converts temperature into electrical voltage?
Thermocouple
Strain gauge
Capacitive pressure sensor
Optical fiber sensor
Explanation - Thermocouples produce a voltage proportional to temperature difference between junctions.
Correct answer is: Thermocouple
Q.81 A 'galvanometer' is a type of:
Voltmeter
Ammeter
Current indicator
Pressure sensor
Explanation - Galvanometers detect and display small currents via needle deflection.
Correct answer is: Current indicator
Q.82 In instrumentation, 'gain' refers to:
The ratio of output to input
The resistance of the meter
The time delay
The input impedance
Explanation - Gain quantifies how much the instrument amplifies the input signal.
Correct answer is: The ratio of output to input
Q.83 What does a 'voltage divider' do?
Amplify voltage
Reduce voltage
Measure current
Measure resistance
Explanation - A voltage divider creates a fraction of the input voltage at its output.
Correct answer is: Reduce voltage
Q.84 The 'full scale error' of an instrument is:
Error at zero input
Error at maximum input
Error at mid‑scale
All of the above
Explanation - Full scale error is the difference between true and indicated maximum reading.
Correct answer is: Error at maximum input
Q.85 A 'magnetic flux density meter' measures:
Electric field
Magnetic field
Temperature
Pressure
Explanation - It measures the strength of a magnetic field, typically in Tesla or Gauss.
Correct answer is: Magnetic field
Q.86 Which of the following is a 'digital indicator' that displays numeric values?
D’Arsonval galvanometer
Digital multimeter
Mercury manometer
Analog voltmeter
Explanation - Digital indicators provide numeric readouts on an LCD or LED display.
Correct answer is: Digital multimeter
Q.87 The 'resolution' of an analog meter depends on:
Scale markings
Coil resistance
Magnetic field strength
All of the above
Explanation - Resolution is limited by how finely the scale can be read on an analog meter.
Correct answer is: Scale markings
Q.88 In a 'moving‑coil' meter, the deflection is proportional to:
Current
Voltage
Resistance
Capacitance
Explanation - The coil in a moving‑coil meter experiences torque proportional to current.
Correct answer is: Current
Q.89 An 'inductive pressure sensor' uses:
Capacitance changes
Inductance changes
Resistance changes
Temperature changes
Explanation - Pressure alters the coil's inductance, producing an electrical output.
Correct answer is: Inductance changes
Q.90 What is a 'magnetostrictive sensor' primarily used for?
Temperature measurement
Pressure measurement
Distance measurement
Speed measurement
Explanation - Magnetostrictive sensors detect changes in magnetic domain alignment for distance sensing.
Correct answer is: Distance measurement
Q.91 Which of the following is a type of 'bridge circuit' used for measuring current?
Wheatstone bridge
Kelvin bridge
Hall‑effect bridge
Current bridge
Explanation - A current bridge uses a known current source to balance an unknown current measurement.
Correct answer is: Current bridge
Q.92 The 'noise figure' of an amplifier indicates:
Its linearity
The amount of noise added
The input impedance
The output voltage
Explanation - Noise figure quantifies how much extra noise the amplifier introduces.
Correct answer is: The amount of noise added
Q.93 An 'optical encoder' is used to measure:
Position
Speed
Temperature
Pressure
Explanation - Optical encoders convert mechanical rotation into digital pulses representing position.
Correct answer is: Position
Q.94 Which instrument is typically used for measuring very small temperature differences?
Thermocouple
Bimetallic thermometer
Thermistor
Resistance temperature detector (RTD)
Explanation - RTDs have high accuracy and can detect small temperature changes.
Correct answer is: Resistance temperature detector (RTD)
Q.95 A 'digital micrometer' is used to measure:
Electrical current
Mechanical dimension
Voltage
Pressure
Explanation - A digital micrometer provides precise measurement of small mechanical dimensions.
Correct answer is: Mechanical dimension
Q.96 Which of the following instruments uses a 'photoelectric effect' for measurement?
Thermocouple
Photoresistor
Capacitive pressure sensor
Strain gauge
Explanation - Photoresistors change resistance based on incident light due to the photoelectric effect.
Correct answer is: Photoresistor
Q.97 In an 'electromagnetic flow meter', the output voltage is:
Proportional to flow velocity
Inversely proportional to flow velocity
Independent of flow
Proportional to pressure
Explanation - The induced voltage in the electrodes is proportional to fluid velocity in a magnetic field.
Correct answer is: Proportional to flow velocity
Q.98 A 'Kelvin connection' is used in instrumentation to:
Measure resistance with high precision
Measure current
Measure voltage
Measure temperature
Explanation - The Kelvin connection eliminates lead resistance errors in resistance measurements.
Correct answer is: Measure resistance with high precision
Q.99 Which instrument is used to detect and measure the frequency of an AC signal in real time?
Oscilloscope
Frequency counter
Ammeter
Thermocouple
Explanation - A frequency counter counts cycles per second to provide a direct frequency reading.
Correct answer is: Frequency counter
Q.100 The 'output' of a strain gauge in a Wheatstone bridge is measured as:
Voltage
Current
Resistance change
Temperature change
Explanation - A Wheatstone bridge converts strain‑induced resistance change into a measurable voltage difference.
Correct answer is: Voltage
Q.101 Which type of sensor is best suited for measuring high pressure in gas pipelines?
Capacitance manometer
Piezoresistive pressure sensor
Mercury manometer
Thermocouple
Explanation - Piezoresistive sensors provide high accuracy and robustness for high‑pressure applications.
Correct answer is: Piezoresistive pressure sensor
Q.102 An 'optical tachometer' measures:
Speed of rotation
Voltage
Temperature
Pressure
Explanation - Optical tachometers use a rotating mask to produce pulses proportional to rotational speed.
Correct answer is: Speed of rotation
Q.103 The 'noise' in an electronic instrument is mainly caused by:
Thermal agitation of electrons
Mechanical vibration
Electrical interference
All of the above
Explanation - Noise can arise from thermal, mechanical, and electromagnetic sources.
Correct answer is: All of the above
Q.104 Which of the following is a 'solid‑state' temperature sensor?
Thermocouple
RTD
Bimetallic thermometer
Mercury thermometer
Explanation - RTDs use solid metal (often platinum) whose resistance changes with temperature.
Correct answer is: RTD
Q.105 An 'electrolytic capacitor' has:
High dielectric strength
Low leakage current
Large physical size for a given capacitance
All of the above
Explanation - Electrolytic capacitors use an electrolyte to achieve large capacitance in a smaller volume.
Correct answer is: Large physical size for a given capacitance
Q.106 Which of the following instruments measures the 'electromotive force' (EMF) of a battery?
Voltmeter
Ammeter
Resistance meter
Thermocouple
Explanation - A voltmeter measures the EMF or voltage between two points of a battery.
Correct answer is: Voltmeter
Q.107 The 'SNR' (signal‑to‑noise ratio) of an instrument is:
Signal strength divided by noise level
Noise level divided by signal strength
Signal minus noise
None of the above
Explanation - SNR quantifies how much stronger the signal is relative to background noise.
Correct answer is: Signal strength divided by noise level
Q.108 Which of these instruments is best for measuring transient electrical spikes?
Digital multimeter
Oscilloscope
Voltmeter
Ammeter
Explanation - Oscilloscopes capture rapid voltage transients with high bandwidth.
Correct answer is: Oscilloscope
Q.109 A 'pressure transducer' converts pressure into:
Temperature
Voltage
Current
All of the above
Explanation - Most pressure transducers output a voltage proportional to the pressure applied.
Correct answer is: Voltage
Q.110 Which instrument is used to measure the 'dielectric constant' of a material?
Capacitance meter
Resistivity meter
Thermal analyzer
Magnetometer
Explanation - A capacitance meter measures capacitance changes that relate to the material's dielectric constant.
Correct answer is: Capacitance meter
Q.111 The 'sensing range' of a transducer is:
The range of physical values it can sense
The range of output voltages
The frequency range
The temperature range
Explanation - Sensing range refers to the limits of the input quantity the transducer can measure.
Correct answer is: The range of physical values it can sense
Q.112 Which of the following is a 'broadband' sensor?
Low‑pass filter
High‑pass filter
Band‑pass filter
Band‑stop filter
Explanation - A band‑pass filter passes a wide range of frequencies around a center frequency.
Correct answer is: Band‑pass filter
Q.113 An 'electrostatic sensor' measures:
Electric field
Magnetic field
Pressure
Temperature
Explanation - Electrostatic sensors detect variations in electric field strength.
Correct answer is: Electric field
Q.114 Which device converts a temperature difference into a voltage?
Thermistor
Thermocouple
Piezoresistor
Capacitor
Explanation - Thermocouples generate a voltage proportional to temperature difference across junctions.
Correct answer is: Thermocouple
Q.115 The 'output impedance' of an instrument refers to:
The resistance to which the instrument is connected
The internal resistance of the instrument's output
The input resistance of the instrument
The impedance of the measurement cable
Explanation - Output impedance describes how the instrument’s output resists current flow.
Correct answer is: The internal resistance of the instrument's output
Q.116 Which of the following instruments is used to measure the 'voltage drop' across a resistor?
Ammeter
Voltmeter
Multimeter
Oscilloscope
Explanation - A voltmeter measures potential difference across any component, including resistors.
Correct answer is: Voltmeter
Q.117 An 'inductive sensor' detects:
Temperature changes
Magnetic field changes
Pressure changes
Light intensity changes
Explanation - Inductive sensors respond to changes in magnetic field or proximity of metal objects.
Correct answer is: Magnetic field changes
Q.118 A 'digital thermometer' displays:
Numeric temperature values
A needle position
A color map
A waveform
Explanation - Digital thermometers read temperature as numbers on a digital screen.
Correct answer is: Numeric temperature values
Q.119 Which of the following is a 'noise source' in a measurement system?
Thermal noise
Shot noise
1/f noise
All of the above
Explanation - All listed phenomena can contribute to measurement noise.
Correct answer is: All of the above
Q.120 A 'current probe' can be used to measure:
Direct current
Alternating current
Both DC and AC
Neither
Explanation - Current probes can be designed to sense both DC and AC currents.
Correct answer is: Both DC and AC
Q.121 Which of the following is a 'temperature‑to‑frequency' converter?
Thermocouple
Thermistor
RTD
Capacitive sensor
Explanation - Thermistors can be part of oscillators producing frequency changes with temperature.
Correct answer is: Thermistor
Q.122 An 'optical interferometer' is used to measure:
Electrical current
Optical path length changes
Pressure
Temperature
Explanation - Interferometers detect minute changes in optical path length via interference patterns.
Correct answer is: Optical path length changes
Q.123 Which instrument has the highest input impedance?
Ammeter
Voltmeter
Thermocouple
Digital multimeter
Explanation - Thermocouples present a very high input impedance, minimizing loading effects.
Correct answer is: Thermocouple
Q.124 Which of these instruments is best suited for measuring dynamic pressure variations?
Static pressure sensor
Differential pressure sensor
Strain gauge
Thermocouple
Explanation - Differential pressure sensors can capture rapid pressure changes between two points.
Correct answer is: Differential pressure sensor
Q.125 A 'Hall‑effect sensor' measures:
Temperature
Magnetic field strength
Pressure
Voltage
Explanation - Hall‑effect sensors detect magnetic field strength via voltage generated in a conductor.
Correct answer is: Magnetic field strength
Q.126 In a 'Wheatstone bridge', the output voltage is zero when:
The bridge is unbalanced
The bridge is balanced
The input voltage is zero
The resistances are unequal
Explanation - When the ratios of the two branches are equal, the output is zero.
Correct answer is: The bridge is balanced
Q.127 Which instrument is used to measure the 'dielectric loss' of a material?
Dielectric spectrometer
Thermistor
Capacitance meter
Resistance meter
Explanation - Dielectric spectrometers evaluate loss tangent and permittivity across frequencies.
Correct answer is: Dielectric spectrometer
Q.128 A 'piezoresistive pressure sensor' uses:
Capacitance change
Resistance change
Inductance change
Temperature change
Explanation - Piezoresistive sensors change resistance under applied pressure, producing an electrical output.
Correct answer is: Resistance change
Q.129 An 'optical fiber sensor' can measure:
Temperature
Strain
Both temperature and strain
Electrical current
Explanation - Optical fiber sensors detect changes in temperature or strain via optical signal variations.
Correct answer is: Both temperature and strain
Q.130 Which instrument uses a 'photoelastic' effect for measurement?
Thermocouple
Strain gauge
Photoelastic sensor
Capacitive pressure sensor
Explanation - Photoelastic sensors measure stress by changes in birefringence of a material under stress.
Correct answer is: Photoelastic sensor
Q.131 A 'differential amplifier' is commonly used to:
Amplify a single‑ended signal
Amplify the difference between two signals
Reduce the frequency of a signal
Measure resistance
Explanation - Differential amplifiers amplify the voltage difference between two input terminals.
Correct answer is: Amplify the difference between two signals
Q.132 A 'temperature coefficient of resistance' (TCR) refers to:
Change in resistance per degree change in temperature
Change in voltage per degree change in temperature
Change in current per degree change in temperature
Change in capacitance per degree change in temperature
Explanation - TCR quantifies how much a resistor’s resistance changes with temperature.
Correct answer is: Change in resistance per degree change in temperature
Q.133 Which of the following is an example of a 'solid‑state' pressure sensor?
Piezoresistive sensor
Capacitance manometer
Piezoceramic sensor
All of the above
Explanation - All listed sensors are solid‑state and convert pressure to electrical signals.
Correct answer is: All of the above
Q.134 An 'optical encoder' is typically used for:
Measuring temperature
Measuring speed and position
Measuring pressure
Measuring voltage
Explanation - Optical encoders translate mechanical rotation into digital codes for speed and position.
Correct answer is: Measuring speed and position
Q.135 Which of the following instruments measures the 'magnetic flux density' directly?
Fluxgate magnetometer
Hall‑effect sensor
Magnetometer
All of the above
Explanation - All listed devices can directly measure magnetic flux density.
Correct answer is: All of the above
Q.136 In instrumentation, the 'scale factor' is:
The ratio of output to input
The maximum input value
The sensitivity
The zero offset
Explanation - The scale factor converts instrument output back into physical units.
Correct answer is: The ratio of output to input
Q.137 A 'digital voltmeter' typically uses:
Analog amplification only
An analog‑to‑digital converter (ADC)
A mechanical potentiometer
A mercury column
Explanation - Digital voltmeters convert analog voltage into a digital representation via an ADC.
Correct answer is: An analog‑to‑digital converter (ADC)
Q.138 Which of the following is used to measure the 'frequency response' of an electronic circuit?
Spectrum analyzer
Oscilloscope
Ammeter
Thermometer
Explanation - A spectrum analyzer displays the amplitude of signals versus frequency.
Correct answer is: Spectrum analyzer
Q.139 A 'lock‑in amplifier' is designed to extract:
High‑frequency signals
Weak signals from noise
DC voltages
Temperature variations
Explanation - Lock‑in amplifiers use synchronous detection to isolate weak signals buried in noise.
Correct answer is: Weak signals from noise
Q.140 In a 'Kelvin connection', the purpose of the second pair of wires is to:
Reduce series resistance
Provide a reference voltage
Measure voltage drop
Isolate the device
Explanation - The Kelvin pair eliminates lead resistance, enabling precise resistance measurement.
Correct answer is: Reduce series resistance
Q.141 A 'broadband microphone' is used for:
Measuring pressure
Measuring voltage
Measuring sound pressure level
Measuring current
Explanation - Broadband microphones can capture a wide range of sound frequencies for sound level measurements.
Correct answer is: Measuring sound pressure level
Q.142 The 'input impedance' of a voltmeter is typically:
Low
Medium
High
Variable
Explanation - High input impedance minimizes loading effects on the measured circuit.
Correct answer is: High
Q.143 Which instrument is used to measure the 'phase difference' between two signals?
Phase‑locked loop (PLL)
Frequency counter
Oscilloscope with phase meter
Ammeter
Explanation - Oscilloscopes can display two signals and provide phase difference measurement.
Correct answer is: Oscilloscope with phase meter
Q.144 Which of the following instruments uses a 'capacitive sensor' to measure displacement?
Capacitance displacement sensor
Resistive displacement sensor
Strain gauge displacement sensor
Optical displacement sensor
Explanation - Capacitance displacement sensors detect changes in capacitance with physical movement.
Correct answer is: Capacitance displacement sensor
Q.145 An 'electrostatic discharge (ESD) detector' measures:
Electric field intensity
Magnetic field intensity
Temperature
Pressure
Explanation - ESD detectors monitor electric fields that may cause static discharge events.
Correct answer is: Electric field intensity
Q.146 Which of the following devices can act as an 'electromagnetic interference (EMI) shield'?
Copper mesh
PVC pipe
Aluminum foil
Both A and C
Explanation - Copper mesh and aluminum foil can reflect or absorb EMI, providing shielding.
Correct answer is: Both A and C
Q.147 A 'laser interferometer' can measure:
Displacement with sub‑nanometer resolution
Temperature with high accuracy
Electric field with high precision
Magnetic field with high sensitivity
Explanation - Laser interferometers are used for extremely precise displacement measurement.
Correct answer is: Displacement with sub‑nanometer resolution
Q.148 Which of these is an example of a 'solid‑state' temperature sensor with a wide temperature range?
Bimetallic strip
RTD
Thermocouple
Mercury thermometer
Explanation - Thermocouples can operate over a wide temperature range and are solid‑state devices.
Correct answer is: Thermocouple
Q.149 An 'optical fiber gyroscope' measures:
Rotation rate
Acceleration
Temperature
Voltage
Explanation - Optical fiber gyroscopes detect rotation via the Sagnac effect.
Correct answer is: Rotation rate
Q.150 A 'strain gauge bridge' typically uses a Wheatstone configuration to detect:
Voltage
Current
Resistance change due to strain
Temperature change
Explanation - The Wheatstone bridge converts the strain‑induced resistance change into a voltage difference.
Correct answer is: Resistance change due to strain
Q.151 Which instrument measures the 'dielectric loss tangent' of a material?
Dielectric spectrometer
Thermistor
Capacitance meter
Oscilloscope
Explanation - Dielectric spectrometers provide loss tangent and permittivity data across frequencies.
Correct answer is: Dielectric spectrometer
Q.152 A 'magnetic fluxgate sensor' is primarily used for:
Temperature measurement
Magnetic field detection
Pressure sensing
Current measurement
Explanation - Fluxgate sensors detect extremely small magnetic fields with high sensitivity.
Correct answer is: Magnetic field detection
Q.153 An 'ultrasonic displacement sensor' operates by:
Measuring electrical resistance changes
Detecting reflected sound waves
Measuring temperature changes
Using magnetic induction
Explanation - It emits ultrasonic waves and measures time‑of‑flight to determine displacement.
Correct answer is: Detecting reflected sound waves
Q.154 Which of the following is used for measuring the 'electrostatic potential difference' between two points?
Voltmeter
Ammeter
Thermocouple
Barometer
Explanation - Voltmeters measure potential difference, which is essentially electrostatic potential difference.
Correct answer is: Voltmeter
Q.155 A 'piezoceramic sensor' is used in:
Temperature measurement
Pressure measurement
Acceleration measurement
All of the above
Explanation - Piezoceramic sensors can convert mechanical stimuli into electrical signals and vice versa.
Correct answer is: All of the above
Q.156 In a 'digital frequency counter', the resolution is determined by:
Sampling frequency
Counting interval
Amplifier gain
Input impedance
Explanation - Resolution depends on the time over which cycles are counted.
Correct answer is: Counting interval
Q.157 A 'thermistor' typically has a negative temperature coefficient (NTC) because:
Its resistance increases with temperature
Its resistance decreases with temperature
Its resistance is independent of temperature
It is not used in temperature sensing
Explanation - NTC thermistors exhibit decreasing resistance as temperature rises.
Correct answer is: Its resistance decreases with temperature
Q.158 The 'zero point' of an instrument is set by:
Adjusting the scale
Applying a reference voltage
Setting the zero‑adjust switch
Changing the input impedance
Explanation - Zero‑adjust allows the instrument to read zero when no physical quantity is present.
Correct answer is: Setting the zero‑adjust switch
Q.159 Which of the following sensors is best for measuring liquid temperature?
Thermocouple
Thermistor
RTD
All of the above
Explanation - All listed sensors can measure liquid temperature, with varying accuracy and range.
Correct answer is: All of the above
Q.160 The 'dynamic range' of an instrument refers to:
The range over which it can operate without saturation
The range of temperatures it can measure
The frequency range of the input signal
The noise floor of the instrument
Explanation - Dynamic range is the span between the smallest and largest detectable signals.
Correct answer is: The range over which it can operate without saturation
Q.161 A 'digital logic analyzer' is used to:
Measure analog voltage
Capture digital waveforms
Measure temperature
Measure pressure
Explanation - Logic analyzers record digital signals for debugging digital circuits.
Correct answer is: Capture digital waveforms
Q.162 Which of the following devices measures the 'temperature coefficient of frequency' of an oscillator?
Temperature controller
Frequency counter
Oscillator with built‑in temperature sensor
All of the above
Explanation - These devices can be used to measure how an oscillator’s frequency changes with temperature.
Correct answer is: All of the above
Q.163 An 'optical fiber strain sensor' operates by:
Measuring changes in light intensity
Measuring changes in light phase
Measuring changes in light polarization
All of the above
Explanation - Optical fiber strain sensors can detect intensity, phase, or polarization changes caused by strain.
Correct answer is: All of the above
Q.164 Which of the following is used to measure the 'inductance' of a coil?
LCR meter
DMM
Oscilloscope
Ammeter
Explanation - An LCR meter can measure inductance (L), capacitance (C), and resistance (R).
Correct answer is: LCR meter
Q.165 A 'dual‑phase lock‑in amplifier' is particularly useful for:
Measuring large signals
Measuring signals with phase shifts
Measuring static signals
Measuring temperature
Explanation - Dual‑phase lock‑in amplifiers can detect both in‑phase and out‑of‑phase components.
Correct answer is: Measuring signals with phase shifts
Q.166 An 'optical sensor' that uses 'photodiodes' is often used for:
Temperature measurement
Light intensity measurement
Pressure measurement
Sound level measurement
Explanation - Photodiodes produce current proportional to incident light intensity.
Correct answer is: Light intensity measurement
Q.167 A 'digital pressure gauge' typically uses which transducer type?
Piezoresistive
Capacitive
Piezoelectric
All of the above
Explanation - Digital pressure gauges may employ any of these transducer technologies.
Correct answer is: All of the above
Q.168 The 'bandwidth' of an oscilloscope is:
The maximum input voltage
The maximum frequency it can accurately display
The maximum time base
The maximum resolution
Explanation - Bandwidth determines the highest frequency component the oscilloscope can display correctly.
Correct answer is: The maximum frequency it can accurately display
Q.169 An 'electro‑optic sensor' works by:
Changing resistance with electric field
Changing refractive index with electric field
Changing capacitance with temperature
Changing inductance with magnetic field
Explanation - Electro‑optic sensors exploit the electro‑optic effect where the refractive index changes with an applied electric field.
Correct answer is: Changing refractive index with electric field
Q.170 Which of the following is NOT a type of strain gauge?
Resistive strain gauge
Capacitive strain gauge
Piezoelectric strain gauge
Magnetic strain gauge
Explanation - Strain gauges are generally resistive, capacitive, or piezoelectric; there is no common magnetic strain gauge.
Correct answer is: Magnetic strain gauge
Q.171 A 'digital temperature sensor' typically outputs:
Analog voltage
Digital binary code
PWM signal
None of the above
Explanation - Digital temperature sensors often provide a digital readout directly to a microcontroller.
Correct answer is: Digital binary code
Q.172 Which device is used to measure the 'magnetic hysteresis' of a material?
Hysteresis loop tracer
Magnetometer
Capacitance meter
Resistance meter
Explanation - A hysteresis loop tracer measures the relationship between magnetic flux and magnetic field.
Correct answer is: Hysteresis loop tracer
Q.173 The 'full‑scale error' in a digital multimeter is:
The error at zero input
The error at maximum input
The error at mid‑scale
The error in calibration
Explanation - Full‑scale error is the difference between true and displayed value at the instrument’s full‑scale reading.
Correct answer is: The error at maximum input
Q.174 In a Wheatstone bridge, a change in one resistor due to strain causes:
A change in output voltage
A change in input voltage
A change in bridge balance
Both A and C
Explanation - Strain changes the resistor’s value, altering output voltage and causing the bridge to become unbalanced.
Correct answer is: Both A and C
Q.175 Which instrument can be used to measure the 'electric field strength' of a static electric field?
E‑field probe
Magnetometer
Voltmeter
Ammeter
Explanation - An electric field probe measures static electric field strength directly.
Correct answer is: E‑field probe
Q.176 A 'piezoelectric sensor' converts mechanical stress into:
Voltage
Current
Resistance
Capacitance
Explanation - Piezoelectric materials generate an electric charge (voltage) when mechanically stressed.
Correct answer is: Voltage
Q.177 The 'resolution' of a digital thermometer is determined by:
The ADC resolution
The sensor’s sensitivity
The power supply voltage
The temperature range
Explanation - The ADC’s resolution dictates how finely the thermometer can display temperature values.
Correct answer is: The ADC resolution
Q.178 A 'hydraulic gauge' is used to measure:
Liquid pressure
Liquid temperature
Liquid flow
Liquid density
Explanation - Hydraulic gauges measure the pressure in hydraulic systems.
Correct answer is: Liquid pressure