22. Which of the following devices can be used to detect radiant heat ? A.Liquid thermometer B.Six's maximum and minimum thermometer C.Constant volume air thermometer D.Thermopile
Option D Solution: Based on the thermoelectric effect, the thermopile can be used as a heat sensor to measure thermal radiation. A thermopile is made of thermocouple junction pairs connected electrically in series. Thermocouples near the ground measures radiant energy.
