Question 39General Subjects - QMED

A) Bimetallic thermometer is the correct answer. A bimetallic thermometer works on the principle of differential expansion of two dissimilar metals as the temperature rises. This causes the bimetallic strip to bend, which in turn moves a rotary dial scale to indicate the temperature. This type of direct reading thermometer is commonly used in various applications, including the US Coast Guard Captain's License Examinations. The other options are incorrect because: B) Liquid-in-glass thermometers use the expansion of a liquid, C) Bourdon tube thermometers use the expansion of a gas, and D) Thermocouple pyrometers measure temperature based on the thermoelectric effect, not the differential expansion of metals.