Speed of EM wave in medium = C/√(εr*μr)
= 1*10⁸ m/s
A thermopile is an electronic device that converts thermal energy into electrical energy.
It is composed of several thermocouples connected usually in series or less commonly, in parallel.
Thermopiles are used for contactless temperature sensing.
The function of a thermopile is to transfer the heat radiation emitted from the object to a voltage output.
The output is in the range of tens or hundreds of millivolts.