This condition is generally true in thermal conduction ( where it is guaranteed by Fourier 's law ) .
It is often only approximately true in conditions of convective heat transfer , where a number of physical processes make effective heat transfer coefficients somewhat dependent on temperature differences .
This condition is generally true in thermal conduction ( where it is guaranteed by Fourier 's law ) , but it is often only approximately true in conditions of convective heat transfer , where a number of physical processes make effective heat transfer coefficients somewhat dependent on temperature differences .