Sensors and Actuators – MCQs

1. : What type of sensor is used to detect temperature?
(A) Photodiode
(B) Thermistor
(C) LDR
(D) Accelerometer

2. : Which sensor is typically used in proximity sensing applications?
(A) Thermocouple
(B) Ultrasonic sensor
(C) Gyroscope
(D) Strain gauge

3. : What is the function of an actuator?
(A) Measure physical quantities
(B) Process signals
(C) Convert electrical signals into physical movement
(D) Amplify signals

4. : A piezoelectric sensor generates voltage in response to:
(A) Temperature
(B) Magnetic field
(C) Pressure or vibration
(D) Light

5. : Which of the following is a contact-type sensor?
(A) Proximity sensor
(B) Ultrasonic sensor
(C) Limit switch
(D) Infrared sensor

6. : Which sensor detects changes in magnetic fields?
(A) Hall effect sensor
(B) Thermistor
(C) Phototransistor
(D) Accelerometer

7. : What kind of actuator is a stepper motor?
(A) Linear actuator
(B) Pneumatic actuator
(C) Rotational actuator
(D) Hydraulic actuator

8. : What does an accelerometer measure?
(A) Temperature
(B) Speed
(C) Light
(D) Acceleration or vibration

9. : LDR is used to measure:
(A) Temperature
(B) Humidity
(C) Light intensity
(D) Pressure

10. : Which sensor is suitable for distance measurement using sound?
(A) Infrared sensor
(B) Ultrasonic sensor
(C) LVDT
(D) Hall sensor

11. : A DC motor is an example of a:
(A) Sensor
(B) Transducer
(C) Actuator
(D) Controller

12. : What is the principle behind the working of LVDT?
(A) Inductance
(B) Capacitance
(C) Resistance
(D) Piezoelectricity

13. : A photodiode generates current when exposed to:
(A) Heat
(B) Light
(C) Sound
(D) Pressure

14. : Which actuator converts electrical energy into mechanical motion using magnetic fields?
(A) Pneumatic actuator
(B) Hydraulic actuator
(C) Electric motor
(D) Thermoelectric actuator

15. : A strain gauge measures:
(A) Pressure
(B) Force
(C) Strain
(D) Temperature

16. : The output of a sensor is generally a:
(A) Mechanical signal
(B) Thermal signal
(C) Electrical signal
(D) Optical signal

17. : An actuator receives a signal from a:
(A) Sensor
(B) Microcontroller
(C) Resistor
(D) Capacitor

18. : Which type of actuator is often used in robotics for precise angular motion control?
(A) Pneumatic actuator
(B) Solenoid
(C) Stepper motor
(D) Thermal actuator

19. : A thermocouple works on the principle of:
(A) Seebeck effect
(B) Hall effect
(C) Piezoelectric effect
(D) Joule effect

20. : A load cell is commonly used to measure:
(A) Temperature
(B) Humidity
(C) Force or weight
(D) Light

21. : What kind of signal does a sensor produce?
(A) Control signal
(B) Feedback signal
(C) Input signal
(D) Output signal

22. : A solenoid is a type of:
(A) Sensor
(B) Actuator
(C) Display
(D) Resistor

23. : MEMS-based sensors are commonly used in:
(A) Washing machines
(B) Mobile phones
(C) Street lights
(D) Light bulbs

24. : Which of the following is not a type of actuator?
(A) Motor
(B) Solenoid
(C) Thermocouple
(D) Hydraulic piston

25. : The resolution of a sensor refers to its:
(A) Cost
(B) Physical size
(C) Sensitivity to light
(D) Smallest detectable change