In a special test for determining the performance of a heat exchanger, an electric heater produces a temperature variation in an airflow that can be approximated with a 1-Hz sine wave. The air temperature is measured downstream of the heater with a thermocouple that has a time constant of 0.2 s. The maximum and minimum temperature values measured by the thermocouple are 1200 and 1000 C, respectively.
(a) Determine the equation for the measured variation of temperature.
(b) Determine the actual variation in the air temperature.
(c) Draw the actual and the measured temperature as a function of time.