Data Communications MCQs December 4, 2025August 23, 2024 by u930973931_answers 50 min Score: 0 Attempted: 0/50 Subscribe 1. What is the primary function of an instrument in a measurement system? (A) To store data (B) To control processes (C) To measure physical quantities (D) To process data 2. Which type of sensor converts physical quantity into an electrical signal? (A) Actuator (B) Indicator (C) Controller (D) Transducer 3. What does a “thermocouple” measure? (A) Flow rate (B) Pressure (C) Humidity (D) Temperature 4. What is the principle behind a “strain gauge”? (A) It measures flow rate by detecting changes in frequency (B) It measures pressure by detecting changes in capacitance (C) It measures temperature by detecting changes in voltage (D) It measures strain by detecting changes in resistance 5. Which device is used to measure the flow rate of a liquid? (A) Hygrometer (B) Pressure gauge (C) Thermometer (D) Flowmeter 6. What does a “manometer” measure? (A) Temperature (B) Speed (C) Pressure (D) Distance 7. What is the main use of a “calibration” process in instrumentation? (A) To reduce measurement noise (B) To improve the sensor’s sensitivity (C) To increase the measurement range (D) To ensure accuracy and precision of measurements 8. Which type of measurement does a “pH meter” perform? (A) Temperature (B) pH level (C) Humidity (D) Pressure 9. What is the function of a “pressure transducer”? (A) To determine flow rate (B) To measure temperature changes (C) To convert pressure into an electrical signal (D) To measure humidity 10. What does an “oscilloscope” display? (A) The pressure of a fluid (B) The temperature of an object (C) The waveform of electrical signals (D) The pH of a solution 11. What type of sensor is a “piezoelectric sensor”? (A) It measures temperature by resistance change (B) It detects light intensity by varying resistance (C) It measures pressure by capacitive change (D) It converts mechanical stress into electrical charge 12. What does a “displacement sensor” measure? (A) The pressure of a fluid (B) The distance or change in position of an object (C) The temperature of an object (D) The flow rate of a liquid 13. What is an “RTD” used to measure? (A) Pressure (B) Temperature (C) Flow rate (D) Humidity 14. What is the purpose of an “instrumentation amplifier”? (A) To filter noise from signals (B) To measure temperature changes (C) To amplify low-level signals with high precision (D) To convert analog signals to digital 15. Which type of sensor uses a “capacitive” principle? (A) Capacitive proximity sensor (B) Thermocouple (C) Resistive temperature device (RTD) (D) Strain gauge 16. What is a “hall effect sensor” used to measure? (A) Temperature (B) Magnetic fields (C) Pressure (D) Displacement 17. In a “data acquisition system,” what is the role of an “analog-to-digital converter (ADC)”? (A) To amplify digital signals (B) To convert analog signals into digital signals (C) To measure analog signals (D) To filter analog signals 18. What does a “humidity sensor” measure? (A) The temperature of an object (B) The amount of moisture in the air (C) The flow rate of a liquid (D) The pressure of a fluid 19. What does a “gas chromatograph” analyze? (A) The temperature of a fluid (B) The flow rate of a liquid (C) The pressure of a gas (D) The composition of gases or volatile compounds 20. What is the main function of a “vibration sensor”? (A) To measure the frequency and amplitude of vibrations (B) To detect changes in pressure (C) To measure flow rate (D) To measure temperature changes 21. What is the primary use of a “level sensor”? (A) To detect the level of liquids or solids in a container (B) To measure the temperature of a substance (C) To determine the pressure of a fluid (D) To measure the flow rate of a liquid 22. What does a “thermistor” measure? (A) Pressure based on capacitance change (B) Flow rate based on frequency change (C) Temperature based on resistance change (D) pH level based on voltage change 23. What is the function of a “load cell” in instrumentation? (A) To measure force or weight (B) To measure temperature changes (C) To determine fluid flow rate (D) To measure humidity 24. What does a “digital voltmeter” measure? (A) Resistance in a digital format (B) Frequency in a digital format (C) Current in a digital format (D) Voltage in a digital format 25. What principle does a “photoelectric sensor” operate on? (A) It detects changes in pressure (B) It detects changes in light intensity (C) It measures changes in temperature (D) It measures changes in magnetic fields 26. What is the primary function of a “speed sensor”? (A) To determine the flow rate of a liquid (B) To measure the temperature of a fluid (C) To detect the pressure of a gas (D) To measure the speed of rotating or moving objects 27. What type of sensor is a “proximity sensor”? (A) A sensor that measures pressure variations (B) A sensor that measures temperature changes (C) A sensor that detects the presence of nearby objects without physical contact (D) A sensor that measures flow rate 28. What does a “current transformer” measure? (A) Current in an AC circuit (B) Voltage in an AC circuit (C) Power in an AC circuit (D) Resistance in a DC circuit 29. What is the main use of a “frequency meter”? (A) To measure the current in an electrical signal (B) To measure the voltage of an electrical signal (C) To measure the power in an electrical signal (D) To measure the frequency of an electrical signal 30. What does a “gas sensor” measure? (A) The temperature of a gas (B) The flow rate of a gas (C) The pressure of a gas (D) The concentration of specific gases in the environment 31. What does a “differential pressure sensor” measure? (A) The difference in pressure between two points (B) The temperature of a fluid (C) The absolute pressure of a fluid (D) The flow rate of a fluid 32. What is the purpose of a “signal conditioner”? (A) To measure the signal directly (B) To store the signal data (C) To modify the signal to a suitable form for measurement or processing (D) To display the signal 33. What does a “vortex flowmeter” measure? (A) The density of a fluid (B) The pressure of a fluid (C) The flow rate of a fluid using vortex shedding principle (D) The temperature of a fluid 34. What type of measurement does an “inductive proximity sensor” provide? (A) Measurement of temperature (B) Detection of the presence of metal objects (C) Measurement of pressure (D) Measurement of flow rate 35. What does a “photoresistor” change its resistance based on? (A) Pressure (B) Humidity (C) Temperature (D) Light intensity 36. What is a “rheostat” used for? (A) To adjust the resistance in a circuit (B) To measure temperature (C) To measure pressure (D) To measure flow rate 37. What does a “humidity sensor” typically use to measure moisture content? (A) Capacitive or resistive principles (B) Optical or acoustic principles (C) Magnetic or inductive principles (D) Thermal or piezoelectric principles 38. What does a “digital multimeter” measure? (A) Voltage, current, and resistance (B) Pressure and temperature (C) Flow rate and humidity (D) Speed and displacement 39. What principle does a “thermocouple” use to measure temperature? (A) The piezoelectric effect due to temperature changes (B) The resistance change due to temperature (C) The capacitance change due to temperature (D) The Seebeck effect, where a voltage is generated due to different metals at different temperatures 40. What is a “Bourdon tube” used for in instrumentation? (A) To measure flow rate (B) To measure temperature (C) To measure displacement (D) To measure pressure 41. What does a “tachometer” measure? (A) The temperature of an object (B) The rotational speed of a shaft or wheel (C) The pressure of a fluid (D) The flow rate of a liquid 42. What is the function of a “thermal imaging camera”? (A) To capture the heat emitted by objects and visualize temperature distribution (B) To determine fluid flow rate (C) To measure pressure variations (D) To measure light intensity 43. What is a “load cell” primarily used for in industrial applications? (A) To measure temperature changes (B) To determine fluid flow rate (C) To measure humidity levels (D) To measure the weight or force applied to it 44. What is an “ultrasonic sensor” used to measure? (A) Pressure by detecting sound frequency changes (B) Distance by emitting sound waves and measuring the reflection time (C) Temperature by measuring sound velocity (D) Flow rate by detecting sound attenuation 45. What does a “pneumatic pressure transducer” convert? (A) Electrical signals into pneumatic pressure (B) Pneumatic pressure into an electrical signal (C) Fluid flow into electrical signals (D) Temperature into pneumatic pressure 46. What does a “capacitive level sensor” measure? (A) The level of liquids or solids based on changes in capacitance (B) The pressure of a gas (C) The temperature of a fluid (D) The flow rate of a liquid 47. What does a “radar level sensor” use to measure level? (A) Temperature changes to determine the level (B) Acoustic waves to measure the distance (C) Pressure changes to measure the level (D) Radio waves to detect the distance to the surface of the material 48. What is the main advantage of using an “optical sensor”? (A) It is highly sensitive to temperature changes (B) It provides non-contact measurement with high precision (C) It can measure pressure changes effectively (D) It provides high-speed measurement for flow rates 49. What does a “magnetostrictive sensor” measure? (A) Temperature by measuring resistance changes (B) Pressure by detecting capacitance changes (C) Distance by detecting changes in magnetic properties (D) Flow rate by measuring frequency changes 50. What does a “spectrometer” measure in terms of light? (A) The intensity and wavelength distribution of light (B) The distance and displacement of light (C) The speed and flow rate of light (D) The temperature and pressure of light