What device is used to measure temperature within an aircraft engine?

• A. A pressure gauge
• B. A voltmeter
• C. A thermocouple
• D. A tachometer

Answer: (C)

A thermocouple is used to measure temperature within an aircraft engine due to its ability to provide accurate temperature readings in high-temperature environments. This device consists of two different metals joined at one end, which produces a voltage that correlates with temperature differences between the junction and the other end of the metals. In aircraft engines, which operate under extreme conditions, thermocouples are preferred because they are durable, quick to respond to temperature changes, and can measure a wide range of temperatures effectively.

In contrast, other devices listed serve different purposes. A pressure gauge is designed to measure the pressure of fluids or gases, a voltmeter measures electrical voltage, and a tachometer measures rotational speed. None of these devices are suitable for accurately measuring temperature within the engine, emphasizing the specialized role of the thermocouple in this context.