Which material is commonly used in piezoelectric transducers?
A Quartz
B Copper
C Iron
D Aluminum
Quartz exhibits the piezoelectric effect, where mechanical stress generates an electrical charge, making it ideal for sensors.
What does an oscilloscope primarily measure?
A Resistance
B Voltage variations over time
C Power
D Capacitance
Oscilloscopes display the waveform of electrical signals, allowing analysis of voltage changes over time.
What is the dynamic characteristic of an instrument?
A Linearity
B Time constant
C Accuracy
D Sensitivity
The dynamic characteristic of an instrument describes how quickly it responds to changes, with the time constant indicating response speed.
Which type of noise is reduced by using shielding in electrical systems?
A Thermal noise
B Electromagnetic interference (EMI)
C Shot noise
D Flicker noise
Shielding protects signals from external electromagnetic fields, reducing noise and improving accuracy.
What is the purpose of calibration in instruments?
A To increase range
B To ensure accuracy by comparing with a standard
C To reduce power consumption
D To increase response time
Calibration ensures that instruments provide accurate measurements by aligning their readings with reference standards.
Which instrument is primarily used to detect small currents?
A Ammeter
B Galvanometer
C Multimeter
D Wattmeter
Galvanometers are highly sensitive instruments used to detect and measure small currents in circuits.
What is the primary function of a potential transformer?
A To step down voltage for safe measurement
B To measure current
C To amplify signals
D To store energy
Potential transformers reduce high voltage to a measurable level for instruments like voltmeters.
Which type of meter measures the total energy consumption over time?
A Wattmeter
B Energy meter
C Multimeter
D Ammeter
Energy meters record the total energy consumed in a circuit, typically expressed in kilowatt-hours (kWh).
What is the unit of power measured by a wattmeter?
A Amperes
B Watts
C Volts
D Ohms
Wattmeters measure power in watts, which is the product of voltage and current multiplied by the power factor.
What is the purpose of using a Venturi meter?
A To measure pressure
B To measure flow rate of fluids
C To measure temperature
D To measure speed
Venturi meters measure the flow rate by detecting pressure differences across a constriction in the pipe.
What is the primary function of a Wheatstone bridge?
A To measure voltage
B To measure resistance
C To measure capacitance
D To measure current
The Wheatstone bridge is used to measure an unknown resistance by balancing two legs of a bridge circuit.
Which instrument measures the flow rate of a fluid?
A Venturi meter
B Oscilloscope
C Wattmeter
D Galvanometer
A Venturi meter measures the flow rate of fluids by detecting pressure differences across a narrowed section of a pipe.
What is the principle of operation of a strain gauge?
A Resistance changes with strain
B Capacitance changes with displacement
C Voltage changes with temperature
D Magnetic flux changes with current
Strain gauges work on the principle that resistance changes when the material is stretched or compressed.
What does a wattmeter measure?
A Energy
B Power
C Voltage
D Current
Wattmeters measure the real power in a circuit, expressed in watts, by monitoring both voltage and current.
What is the function of an LVDT?
A To measure voltage
B To measure displacement
C To measure temperature
D To measure resistance
LVDTs measure linear displacement by converting mechanical motion into an electrical signal using electromagnetic induction.
Which device measures the frequency of an AC signal?
A Frequency meter
B Ammeter
C Thermocouple
D Galvanometer
Frequency meters measure the number of cycles per second (Hertz) of an alternating current (AC) signal.
What is the purpose of a potential transformer?
A To step down voltage for measurement
B To measure current directly
C To amplify voltage
D To step up current for transmission
Potential transformers are used to step down high voltages to a measurable value for metering and protection devices.
What is the typical application of a current transformer?
A To measure high current safely
B To measure voltage in circuits
C To amplify signals
D To measure resistance
Current transformers are used to step down high current to a lower level, making it safe for measuring and protection.
Which type of error arises due to random variations in the measurement process?
A Systematic error
B Random error
C Gross error
D Instrumental error
Random errors are caused by unpredictable factors like environmental conditions or human inconsistencies in measurement.
What does a thermocouple measure?
A Displacement
B Temperature
C Pressure
D Resistance
Thermocouples measure temperature by generating a voltage proportional to the temperature difference between two junctions.
What is the main purpose of calibration?
A To increase instrument sensitivity
B To compare instrument readings with a standard
C To reduce power consumption
D To improve signal strength
Calibration ensures accuracy by comparing an instrument’s measurements to a known standard or reference.
Which type of sensor uses the piezoelectric effect?
A Pressure sensor
B Temperature sensor
C Speed sensor
D Flow sensor
Piezoelectric sensors utilize materials like quartz to generate electrical signals when subjected to mechanical stress, ideal for pressure measurements.
What does an oscilloscope primarily measure?
A Resistance
B Voltage variations over time
C Power
D Capacitance
An oscilloscope is used to visualize and analyze voltage changes over time in the form of waveforms.
What is the dynamic characteristic of an instrument?
A Linearity
B Time constant
C Accuracy
D Sensitivity
Dynamic characteristics, like time constant, describe how well an instrument responds to rapidly changing inputs.
Which material is commonly used in strain gauges?
A Constantan
B Copper
C Aluminum
D Iron
Constantan is commonly used in strain gauges due to its stable resistance characteristics under strain.
What is the purpose of using a signal conditioner?
A To amplify and filter signals
B To measure current
C To store signals
D To measure power
Signal conditioners process raw signals from sensors by amplifying, filtering, or converting them into usable forms.
What is the unit of energy measured by an energy meter?
A Kilowatt-hour (kWh)
B Volt
C Ampere
D Watt
Energy meters measure electrical energy in kilowatt-hours (kWh), which is a unit of energy consumption over time.
Which type of meter is used to measure power in three-phase circuits?
A Three-phase wattmeter
B Single-phase wattmeter
C Digital multimeter
D Galvanometer
A three-phase wattmeter is used to measure power in three-phase systems, which is common in industrial applications.
What is the principle behind the operation of an ammeter?
A Current creates a magnetic field that deflects a needle
B Voltage causes a deflection of the pointer
C Capacitance variation causes a reading
D Piezoelectric effect causes voltage change
Ammeters operate on the principle that current generates a magnetic field that causes a deflection of a needle or digital display.
Which material is commonly used in piezoelectric transducers?
A Quartz
B Copper
C Iron
D Aluminum
Quartz is commonly used in piezoelectric transducers due to its ability to generate electrical charges when subjected to mechanical stress.
What is the primary function of a dynamometer-type wattmeter?
A Measure energy
B Measure average power in AC and DC circuits
C Measure instantaneous power
D Measure voltage
Dynamometer wattmeters measure average power in AC and DC circuits by utilizing the interaction of magnetic fields produced by fixed and moving coils.
What is the working principle of an energy meter?
A Piezoelectric effect
B Electromagnetic induction
C Magnetic deflection
D Electrostatic attraction
Energy meters use electromagnetic induction to drive a rotating disk proportional to power consumption, measuring total energy over time.
Which type of transducer converts pressure into an electrical signal?
A Thermocouple
B Piezoelectric transducer
C LVDT
D Strain gauge
Piezoelectric transducers generate electrical signals when subjected to mechanical pressure, using the piezoelectric effect.
What is the typical range of a household energy meter?
A 0–100 kWh
B 0–1,000 kWh
C 0–10,000 kWh
D 0–50,000 kWh
Energy meters in households typically measure energy consumption up to 10,000 kWh or more.
Which instrument measures the angular velocity of a rotating shaft?
A Tachometer
B Multimeter
C Frequency meter
D Galvanometer
Tachometers measure the rotational speed or angular velocity of a rotating object, usually in revolutions per minute (RPM).
What is the purpose of an Anderson bridge?
A Measure capacitance
B Measure inductance
C Measure resistance
D Measure voltage
Anderson bridge is a type of AC bridge used for precise measurement of inductance in electrical systems.
What type of error arises due to drift in the components of an instrument?
A Random error
B Systematic error
C Gross error
D Instrumental error
Instrumental errors occur due to issues like drift, aging, or manufacturing defects in the instrument components.
Which transducer is best for displacement measurement?
A Strain gauge
B Thermistor
C LVDT
D Tachometer
Linear Variable Differential Transformers (LVDTs) are precise transducers used for measuring linear displacement based on changes in inductance.
What does a phase meter measure?
A Voltage
B Frequency
C Phase angle between two AC signals
D Current
Phase meters measure the angular phase difference between two AC signals, typically expressed in degrees.
What is the principle of operation of a Hall-effect sensor?
A Electromagnetic induction
B Voltage induced by magnetic field
C Current-induced magnetic field
D Resistance change due to strain
Hall-effect sensors operate on the principle of generating a voltage when a current-carrying conductor is placed in a perpendicular magnetic field.
What does a Kelvin bridge measure?
A Low resistance
B High resistance
C Inductance
D Capacitance
Kelvin bridges are designed to measure very low resistances accurately by compensating for lead and contact resistances.
What does a potentiometer measure?
A Voltage
B Current
C Resistance
D Capacitance
Potentiometers measure an unknown voltage by comparing it to a known reference voltage.
Which sensor uses the Seebeck effect?
A Thermistor
B Thermocouple
C Piezoelectric sensor
D Strain gauge
Thermocouples use the Seebeck effect, generating an electrical voltage based on the temperature difference between their junctions.
What is the typical unit of frequency measured by a frequency meter?
A Joules
B Ohms
C Hertz
D Watts
Frequency meters measure the number of cycles per second of an alternating current signal, expressed in Hertz (Hz).
What type of error occurs due to external electromagnetic interference?
A Gross error
B Systematic error
C Environmental error
D Random error
Environmental errors arise due to external factors like electromagnetic interference or temperature variations.
What is the primary purpose of a signal conditioner?
A Store data
B Amplify and filter signals
C Measure resistance
D Display data
Signal conditioners process the raw data from transducers by amplifying, filtering, or converting it into usable forms for further measurement or analysis.
What is the purpose of a Schering bridge?
A Measure resistance
B Measure capacitance
C Measure inductance
D Measure voltage
Schering bridges are used to measure capacitance and dielectric loss in electrical systems, especially in capacitors.
What does an oscilloscope primarily measure?
A Displacement
B Voltage waveform over time
C Pressure changes
D Temperature variations
Oscilloscopes visually display the shape and characteristics of voltage signals over time, allowing for detailed analysis.
What is the purpose of damping in measuring instruments?
A Reduce sensitivity
B Stabilize the pointer and reduce oscillations
C Amplify the signal
D Increase range
Damping minimizes oscillations in the instrument pointer, allowing it to settle quickly and provide accurate readings.
Which type of transformer is used in metering systems?
A Distribution transformer
B Power transformer
C Instrument transformer
D Auto transformer
Instrument transformers, such as current transformers (CTs) and potential transformers (PTs), are used in metering and protection systems to step down high values for safe measurement.