FAA Powerplant Written Practice Test

What is a typical feature of a thermocouple in fire detection systems?

1. It provides real-time temperature data

2. It detects smoke particles

3. It functions based on liquid expansion

4. It activates a warning signal based on pressure

The correct answer is: It provides real-time temperature data

A thermocouple is a widely used device in fire detection systems due to its ability to provide real-time temperature data. It operates by measuring the voltage generated at the junction of two different metals when exposed to a temperature gradient, which enables it to indicate temperature changes quickly. This characteristic is crucial in fire detection because it allows for immediate monitoring of temperature increases associated with combustion, facilitating prompt response actions to mitigate potential fire hazards. The other options highlight different technologies or principles that do not align with the primary function of a thermocouple. Smoke detection relies on sensing particulate matter, which is outside the scope of a thermocouple's function. Liquid expansion is a principle relevant to other temperature sensing devices, such as liquid-in-glass thermometers, not thermocouples. Pressure changes are typically monitored using pressure sensors rather than thermocouples, which do not provide data related to pressure but rather exclusively to temperature changes.