Which instrument is used to measure very high resistance?
A Multimeter
B Megger
C Ammeter
D Galvanometer
A megger is designed to measure very high resistance, such as insulation resistance in electrical systems.
What type of error is caused by changes in ambient temperature?
A Systematic error
B Random error
C Environmental error
D Gross error
Environmental errors result from external factors like temperature, humidity, and pressure changes, which affect instrument accuracy.
Which principle does a thermistor use?
A Resistance changes with strain
B Resistance changes with temperature
C Voltage changes with displacement
D Capacitance changes with pressure
Thermistors are temperature-sensitive resistors whose resistance changes significantly with variations in temperature.
What does a data acquisition system primarily do?
A Store energy
B Collect and process signals from sensors
C Measure resistance
D Display electrical power
Data acquisition systems capture signals from transducers, process them, and convert them into meaningful data.
Which sensor is used for speed measurement?
A Strain gauge
B Tachometer
C Thermocouple
D Oscilloscope
Tachometers measure the speed of rotation, usually in revolutions per minute (RPM), of a shaft or disk.
What is the purpose of a potential transformer?
A To measure current
B To step down voltage for safe measurement
C To step up power
D To amplify electrical signals
Potential transformers are used to reduce high voltage to a lower level that can be safely measured with instruments like voltmeters.
What is the function of a strain gauge?
A Measure temperature
B Measure strain in a material
C Measure pressure
D Measure current
Strain gauges detect deformation in materials by measuring changes in electrical resistance caused by strain.
What type of bridge is used for capacitance measurement?
A Kelvin bridge
B Maxwell bridge
C Wheatstone bridge
D Schering bridge
Schering bridges are used to measure capacitance and dielectric loss in electrical systems.
Which property of an electrical signal does an oscilloscope display?
A Voltage waveform over time
B Power consumption
C Current flow
D Electrical resistance
Oscilloscopes graphically display voltage signals over time, allowing analysis of their characteristics.
What is the typical unit of energy measured by an energy meter?
A Watts
B Kilowatt-hours
C Joules
D Amperes
Energy meters typically record electrical energy consumption in kilowatt-hours (kWh).
What is the primary purpose of a signal conditioner?
A Measure displacement
B Prepare signals for further processing
C Measure current
D Measure temperature
Signal conditioners amplify, filter, and convert raw signals from sensors into formats suitable for data acquisition systems.
Which type of error occurs due to human mistakes during measurement?
A Random error
B Instrumental error
C Gross error
D Environmental error
Gross errors occur due to operator mistakes, such as incorrect readings, recording errors, or improper use of instruments.
What is the purpose of a Kelvin bridge?
A Measure low resistance
B Measure high resistance
C Measure inductance
D Measure capacitance
Kelvin bridges are designed to measure low resistances accurately by compensating for lead and contact resistances.
What is the working principle of a galvanometer?
A Voltage deflection in a magnetic field
B Current deflection in a magnetic field
C Capacitance changes in response to voltage
D Voltage change due to strain
Galvanometers work on the principle of current deflection in a magnetic field, where current flowing through a coil creates a magnetic field that interacts with an external magnet.
What is the primary purpose of a current transformer?
A To step down high current for safe measurement
B To step up voltage for transmission
C To measure power
D To measure energy consumption
Current transformers reduce high currents to lower, safer levels for measurement by meters or relays.
What is the function of a galvanometer?
A Measure current in high voltage circuits
B Detect small currents
C Measure power in AC circuits
D Measure resistance in resistors
A galvanometer is used to detect small currents, typically in microampere ranges, and is often used in measurement instruments.
Which transducer is used for temperature measurement?
A Strain gauge
B Thermocouple
C LVDT
D Piezoelectric sensor
Thermocouples are used to measure temperature by generating an electrical voltage proportional to the temperature difference between two junctions.
What does a digital multimeter display?
A Digital values of electrical quantities
B Analog waveforms
C Magnetic fields
D Resistance in ohms
Digital multimeters provide precise numerical values for electrical quantities such as voltage, current, and resistance, displayed on a digital screen.
What type of error arises due to imperfections in instrument construction?
A Random error
B Instrumental error
C Environmental error
D Gross error
Instrumental errors arise due to design flaws, manufacturing defects, or calibration issues in measurement instruments.
What is the function of a piezoelectric sensor?
A Convert mechanical stress into an electrical signal
B Measure voltage
C Measure displacement
D Measure temperature
Piezoelectric sensors convert mechanical stress (such as pressure or vibration) into an electrical signal through the piezoelectric effect.
What is the primary function of a multimeter?
A Measure multiple electrical quantities like voltage, current, and resistance
B Measure power
C Measure temperature
D Measure torque
A multimeter is a versatile device that can measure voltage, current, and resistance, and in some cases, capacitance and frequency.
Which of the following bridges is used to measure low resistance?
A Maxwell bridge
B Kelvin bridge
C Wheatstone bridge
D Schering bridge
The Kelvin bridge is designed to measure low resistances accurately by compensating for contact and lead resistances.
What is the primary application of a galvanometer?
A Measure high currents
B Detect and measure small currents
C Measure frequency
D Measure power
A galvanometer is a sensitive instrument that detects and measures small currents in electrical circuits.
What is the working principle of a thermocouple?
A Electromagnetic induction
B Seebeck effect
C Piezoelectric effect
D Capacitance variation
A thermocouple operates on the Seebeck effect, where a temperature difference between two dissimilar metals generates a voltage.
Which device is used to measure electrical energy consumption?
A Ammeter
B Wattmeter
C Energy meter
D Oscilloscope
An energy meter measures the total electrical energy consumed over time, usually expressed in kilowatt-hours (kWh).
What is the purpose of damping in measuring instruments?
A Reduce oscillations and stabilize the pointer
B Increase sensitivity
C Amplify signals
D Reduce power consumption
Damping minimizes oscillations of the moving system, allowing the pointer to settle quickly and accurately.
What is the function of a tachometer?
A Measure current
B Measure speed
C Measure voltage
D Measure torque
A tachometer is used to measure the rotational speed of an object, typically expressed in revolutions per minute (RPM).
Which transducer converts mechanical force into an electrical signal?
A Thermistor
B Piezoelectric transducer
C LVDT
D Oscilloscope
Piezoelectric transducers generate an electrical signal when subjected to mechanical force, utilizing the piezoelectric effect.
Which type of meter measures the power factor of a circuit?
A Wattmeter
B Power factor meter
C Energy meter
D Frequency meter
A power factor meter directly measures the ratio of real power to apparent power in an AC circuit.
What is the working principle of a Hall-effect sensor?
A Electromagnetic induction
B Voltage induced by magnetic field
C Resistance change due to strain
D Capacitance change with pressure
Hall-effect sensors work by generating a voltage when a current-carrying conductor is exposed to a perpendicular magnetic field.
What is the unit of frequency measured by a frequency meter?
A Joules
B Watts
C Hertz
D Ohms
Frequency is measured in Hertz (Hz), which represents the number of cycles per second of a periodic wave.
What does a Kelvin bridge measure?
A Low resistance
B High resistance
C Inductance
D Capacitance
Kelvin bridges are used to measure very low resistances by compensating for lead and contact resistances.
Which of the following instruments uses a permanent magnet?
A Moving coil voltmeter
B Moving iron ammeter
C Frequency meter
D Digital multimeter
A moving coil voltmeter uses a permanent magnet to generate a magnetic field, around which a coil moves to indicate the voltage.
What is the purpose of a signal conditioner?
A To amplify and filter signals
B To measure displacement
C To store data
D To measure current
Signal conditioners prepare raw signals by amplifying, filtering, or converting them to a form suitable for further processing.
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
Household energy meters typically measure energy consumption in the range of 0 to 10,000 kWh or more.
What does a potentiometer measure?
A Voltage
B Current
C Resistance
D Capacitance
A potentiometer measures voltage by comparing it to a known reference voltage, providing a precise measurement.
What is the purpose of a frequency meter?
A Measure resistance
B Measure current
C Measure frequency of an AC signal
D Measure power
A frequency meter measures the number of cycles per second (Hertz) of an alternating current signal.
What is the main purpose of a current transformer?
A Step down current for measurement
B Measure voltage directly
C Step up voltage for transmission
D Amplify power
Current transformers step down high current levels for safe measurement by meters and protection devices.
What is the typical application of a piezoelectric sensor?
A Measure pressure
B Measure temperature
C Measure voltage
D Measure displacement
Piezoelectric sensors are used for pressure measurements because they generate electrical charges when exposed to mechanical stress.
What is the principle of a potential transformer?
A Step down high voltage for measurement
B Step up current for safe measurement
C Measure power consumption
D Measure current directly
Potential transformers step down high voltages to safer, measurable levels for metering and protection.
What is the primary function of a multimeter?
A Measure power
B Measure multiple electrical quantities like voltage, current, and resistance
C Measure temperature
D Measure torque
A multimeter is a versatile device that can measure voltage, current, and resistance, and in some cases, capacitance and frequency.
Which of the following bridges is used to measure low resistance?
A Maxwell bridge
B Kelvin bridge
C Wheatstone bridge
D Schering bridge
The Kelvin bridge is designed to measure low resistances accurately by compensating for contact and lead resistances.
What is the primary application of a galvanometer?
A Measure high currents
B Detect and measure small currents
C Measure frequency
D Measure power
A galvanometer is a sensitive instrument used for detecting and measuring very small electric currents in a circuit.
What is the working principle of a thermocouple?
A Electromagnetic induction
B Seebeck effect
C Piezoelectric effect
D Capacitance variation
A thermocouple operates on the Seebeck effect, where a temperature difference between two dissimilar metals generates a voltage.
Which device is used to measure the electrical power of a circuit?
A Ammeter
B Wattmeter
C Energy meter
D Multimeter
A wattmeter measures the power in an electrical circuit by multiplying the voltage and current, considering the power factor.
What is the unit of electrical power measured by a wattmeter?
A Amperes
B Volts
C Watts
D Ohms
Wattmeters measure power in a circuit in watts, which is the product of voltage and current, adjusted for the power factor.
What does a digital multimeter measure?
A Only current
B Voltage, current, and resistance
C Only resistance
D Frequency only
Digital multimeters are versatile tools that measure voltage, current, and resistance, with many also measuring other parameters like capacitance and frequency.
What is the function of a frequency meter?
A Measure power
B Measure frequency of an electrical signal
C Measure voltage
D Measure capacitance
A frequency meter measures the frequency of an alternating current (AC) signal, typically in Hertz (Hz).
What is the purpose of a current transformer (CT)?
A To step down current for safe measurement
B To step up current for transmission
C To measure voltage
D To store electrical energy
Current transformers (CTs) step down high current values to lower, measurable values for safe measurement and protection purposes in electrical circuits.
What is the function of a potential transformer (PT)?
A Step up voltage for transmission
B Step down voltage for measurement
C Measure current
D Amplify power
Potential transformers reduce high voltage levels to safer, measurable values for use with voltmeters and other measuring instruments.