250+ TOP MCQs on MQ2 Gas Sensor Module and Answers

Advanced Microstrip Antenna Questions and Answers on “Numerical Tool for Antenna Analysis”.

1. What is the use of the MQ2 Gas Sensor?
a) Object Identification
b) To provide 3G Connectivity
c) To measure presence of gas
d) To measure Wi-Fi strength
Answer: c
Calrification: The MQ2 Gas sensor is used to measure the degree of presence of particular types of gases in the surrounding air. It can detect Methane, Butane, LPG and smoke quantities present in the air surrounding the sensor.

2. How many terminals does the MQ2 Gas Sensor have?
a) 1
b) 3
c) 2
d) 4
Answer: d
Calrification: The MQ2 Gas Sensor has 4 terminals. These include the Vcc for accepting positive voltage to power the sensor, GND for ground connections to complete the circuit and activate the sensor, Dout which provides a digital output terminal and an Aout which provides the analog output terminal.

3. Does the MQ2 Gas Sensor have a fixed sensitivity?
a) Yes
b) No
Answer: b
Calrification: The sensitivity of any sensor is its ability to detect the smallest degree of change in the measuring medium that generates an accurate output in the sensor’s terminals. The sensitivity of the MQ2 Gas Sensor is not fixed in itself and can be varied using a potentiometer.

4. What will happen if we supply a voltage of 25V to the Vcc of the MQ2 Gas Sensor?
a) Damage is caused
b) Module will shut down
c) Module will not respond for the time the voltage is applied
d) Module will function normally
Answer: a
Calrification: The MQ2 Gas Sensors are mostly built to work on a voltage of approximately 5V. Any voltage lower than that and the board will not be able to power on, but however any voltage significantly above that and the board may suffer permanent damage.

5. What is the maximum output voltage that the MQ2 Gas Sensor can put out on its analog output pin?
a) 1V
b) 140V
c) 5V
d) 10V
Answer: c
Calrification: The maximum output voltage of the MQ2 Gas Sensor is 5V. Any PPM concentrations within that limit can be detected with accuracy by the sensor. However, one can detect higher or lower PPM concentrations to a certain degree by adjusting the potentiometer.

6. Can the MQ2 Gas Sensor differentiate between two different gases with the same PPM?
a) Yes
b) No
Answer: b
Calrification: The MQ2 Gas Sensor is not designed to tell which gases are present in the air surrounding the module. It can only tell what is the concentration or PPM value of a gas. The nature or name of the gas has to be known beforehand while using this sensor.

7. If the PPM concentration of a gas that is being detected by the MQ2 Gas Sensor increases what will happen to its Digital Output pin?
a) Voltage Increases
b) Voltage Decreases
c) Voltage becomes 0
d) Voltage doesn’t change
Answer: d
Calrification: The MQ2 Gas Sensor has two output pins, one is digital and one is analog. The digital pin can only vary between two voltage levels which corresponds to 2 Logic Levels, 1 and 0 or 5V and 0V respectively. So if a gas is present then the digital output becomes 5V but cannot detect any kind of change in concentration of the gas.

8. If the PPM concentration of a gas that is being detected by the MQ2 Gas Sensor increases what will happen to its Analog Output pin?
a) Voltage Increases
b) Voltage Decreases
c) Voltage becomes 0
d) Voltage doesn’t change
Answer: a
Calrification: The MQ2 Gas Sensor has two output pins, one is digital and one is analog. The analog pin’s voltage is set so that it is directly proportional to the PPM value in the air subject to variation in calibration from the potentiometer, so as the PPM level rises so does the voltage in the analog output pin until it reaches 5V.

9. What is the full form of the abbreviation called PPM?
a) Parts Per Million
b) Parts Per Milligram
c) Parts Per Megagram
d) Parts Per Millilitre
Answer: a
Calrification: The correct full form of the PPM abbreviation is Parts per million. It is a way of measuring the concentration of a particular gas in the air, by using the ratio of it and comparing it to others. For example: 1000 PPM of LPG means that if you count 1 million gas molecules within a closed space, 1000 of them would be LPG molecules while the rest would be other gases.

10. What is the name of the mesh surrounding the MQ2 Gas Sensor?
a) Anti-Heat Mesh
b) Anti-Explosion Mesh
c) Anti-Air Mesh
d) Filtration Mesh
Answer: b
Calrification: The MQ2 Gas Sensor is surrounded by a mesh called Anti-Explosion Mesh. This protects the actual sensor inside from combusting as it remains in a heated condition during normal operation and coming into contact with gases like methane or butane or LPG may ignite the gas and cause dangerous accidents.

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