A method for determining the thermal conductivity k and the specific heat of a material is illustrated in the sketch. Initially the two identical samples of diameter 60 mm and thickness 10 mm and the thin heater are at a uniform temperature of 23.00°C, while surrounded by an insulating powder. Suddenly the heater is energized to provide a uniform heat flux on each of the sample interfaces, and the heat flux is maintained constant for a period of time, . A short time after sudden heating is initiated, the temperature at this interface is related to the heat flux as