Electrical Measurements and Instrumentation MCQs (Part-2)
Which of the following is used to measure the resistance of a component?
A Ohmmeter
B Wattmeter
C Ammeter
D Voltmeter
An ohmmeter is designed to measure the electrical resistance of a component or material. By applying a known voltage and measuring the resulting current, it determines the resistance value. Ohm’s Law is used to calculate the resistance from the observed data.
What is the primary function of a transducer?
A Store data
B Measure current
C Generate power
D Convert physical quantity
A transducer converts one form of energy (such as mechanical, thermal, or light energy) into an electrical signal. This makes it useful in sensors and measurement systems, where physical parameters need to be converted into readable electrical outputs for further analysis.
Which of the following measures voltage in a circuit?
A Ammeter
B Frequency meter
C Voltmeter
D Ohmmeter
A voltmeter is designed to measure the electrical potential difference (voltage) across two points in a circuit. It is connected in parallel with the component or section whose voltage is being measured. A high internal resistance ensures minimal impact on the circuit.
What type of sensor measures temperature?
A Thermocouple
B Piezoelectric sensor
C Pressure sensor
D Strain gauge
A thermocouple is a sensor used to measure temperature by converting thermal energy into an electrical voltage. This voltage is then used to calculate the temperature difference between two junctions. Thermocouples are commonly used in industrial and laboratory temperature measurements.
Which instrument is used for measuring electrical frequency?
A Oscilloscope
B Frequency meter
C Galvanometer
D Multimeter
A frequency meter is specifically designed to measure the frequency of an alternating current (AC) signal. It counts the number of cycles per second, providing accurate frequency readings, typically in hertz (Hz), which are essential for monitoring signal integrity in electrical systems.
What does a wattmeter measure in a circuit?
A Current
B Frequency
C Voltage
D Power
A wattmeter is used to measure the real electrical power consumed by a load in a circuit. It works by measuring both the voltage and current in the circuit and then multiplying them to give the total power in watts. Wattmeters are essential for power management and analysis.
Which type of measurement error occurs due to imperfections in the instrument?
A Systematic error
B Instrumental error
C Random error
D Gross error
Instrumental errors arise due to limitations, wear, or calibration issues within the measuring instrument. These errors can be reduced through proper calibration and maintenance, ensuring accurate and reliable measurements in electrical testing and analysis.
What is the purpose of a signal conditioner in a measurement system?
A Convert signal type
B Filter noise
C Amplify signal
D Store data
A signal conditioner modifies or adjusts the signal from a sensor to make it suitable for further processing or measurement. This may include filtering, amplifying, or converting the signal into a more usable format. Signal conditioning is crucial for ensuring signal integrity in data acquisition systems.
What is measured by a strain gauge?
A Voltage
B Strain
C Pressure
D Current
A strain gauge measures the deformation (strain) of an object when a force is applied. It operates on the principle that the resistance of a material changes with its deformation. Strain gauges are used in structural testing and load monitoring applications.
What does a current transformer (CT) primarily do?
A Measure current
B Step up voltage
C Measure resistance
D Step down current
A current transformer (CT) is used to step down high current levels in a power circuit to a lower, safer value that can be measured by instruments. CTs provide isolation between the high-voltage system and the measuring equipment, preventing damage to instruments and ensuring accurate current readings.
In which scenario would you use a potential transformer (PT)?
A For voltage measurement
B For strain measurement
C For power measurement
D For current measurement
A potential transformer (PT) is used to measure high voltages by stepping them down to lower, measurable levels. It is commonly employed in power distribution systems to monitor voltage levels safely and accurately without exposing measurement instruments to high voltages.
Which instrument is used to measure the phase difference between two signals?
A Voltmeter
B Frequency meter
C Oscilloscope
D Phase meter
A phase meter measures the phase difference between two electrical signals. This is particularly useful in alternating current (AC) systems to analyze the relationship between voltage and current, ensuring that they are in sync for efficient power transfer.
What is the main function of an energy meter?
A Measure power
B Measure energy consumption
C Measure voltage
D Measure resistance
An energy meter is designed to measure the total electrical energy consumed by a load over time. It is typically calibrated in kilowatt-hours (kWh) and is commonly used by utility companies for billing purposes. Modern energy meters can also track real time usage and provide remote monitoring capabilities.
Which of the following is used to measure very high voltages?
A High voltage probe
B Strain gauge
C Ammeter
D Wattmeter
A high voltage probe is used to safely measure voltages in high voltage systems, ensuring that the measurement device is isolated from the high voltage circuit. These probes are essential in electrical power systems, especially in areas where voltages exceed standard measurement levels.
What is the role of a bridge circuit in electrical measurements?
A Filter signals
B Convert AC to DC
C Measure resistance accurately
D Measure power
A bridge circuit, such as the Wheatstone bridge, is used to measure resistance with high accuracy. By balancing two legs of the bridge, the unknown resistance can be calculated precisely. Bridge circuits are widely used in laboratories and industrial settings for accurate resistance measurements.