1. Units for Due point is _______
a) gram/m3
b) % by volume
c) PPMV
d) oC
Explanation: Dew point is defined as temperature at which the water vapor in a gas condenses to liquid water and has a units of oC.
2. Humidity sensors are divided into how many types and depending on what?
a) 2 types depending on output
b) 2 types depending on measurement units
c) 3 types depending on measurement units
d) 3 types depending on output
Explanation: According to the measurement units, humidity sensors are divided into two types: Relative Humidity(RH), and Absolute Humidity(moisture) sensors. Most humidity sensors are relative humidity sensors and use different sensing principles.
3. Electronic type hygrometers are divided into how many types?
a) 5 types
b) 3 types
c) 4 types
d) 2 types
Explanation: Electronic type hygrometers or humidity sensors can broadly divided into two categories: one employs capacitive sensing principle, while other use resistive effects.
4. Relative humidity is a function of ________
a) Ambient temperature
b) Water vapor pressure
c) Ambient temperature and Water vapor pressure
d) Dryness
Explanation: Relative humidity is a function of both ambient temperature and water vapor pressure. Therefore there is a relationship between relative humidity, the amount of moisture present in the sensor, and sensor capacitance. This relation governs the operation of a capacitive humidity instrument.
5. Which sensors measure the moisture level using humidity?
a) Capacitive Sensor
b) Resistive Sensor
c) Thermal Conductivity
d) Both resistive and conductive
Explanation: These sensors measure moisture levels using a humidity dependent condenser; they are suitable for RH range and condensation tolerance. These sensors are commonly used in industrial and commercial environments.
6. ________ sensors measure the electrical change in devices such as conductive polymers.
a) Capacitive Sensor
b) Resistive Sensor
c) Thermal Conductivity
d) Both resistive and conductive
Explanation: Both resistive and conductive sensors can measure the electrical change in devices such as conductive polymers and treated substrates. They are suitable for use in residential and commercial environments.
7. ________ sensors are suitable for environments that have high temperatures.
a) Capacitive Sensor
b) Resistive Sensor
c) Thermal Conductivity
d) Both resistive and conductive
Explanation: These sensors are suitable for use in environments that have high temperatures. They measure humidity by calibrating the difference between the thermal conductivity of dry air and that of moist air.
8. Are capacitive sensors linear?
a) True
b) False
Explanation: Capacitive type sensors are linear and hence can measure RH from 0% to 100%, but require complex circuit and also need regular calibration.
9. Capacitive RH sensors dominate __________ measurements.
a) Atmospheric
b) Process
c) Both atmospheric and process
d) Neither atmospheric nor process
Explanation: Capacitive RH sensors dominate atmospheric and process measurements and are the only types of full range RH measuring devices capable of operating accurately down to 0% RH.
10. Which sensor can detect nearby objects?
a) Proximity sensor
b) Humidity sensor
c) Touch sensor
d) Pressure sensor
Explanation: A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation, and looks for a change in the return signal.