What is "temperature coefficient"

n. (context sciences English) A coefficient which relates the change of the magnitude of a physical property to a unit change in temperature.

A temperature coefficient describes the relative change of a physical property that is associated with a given change in temperature. For a property R that changes by dR when the temperature changes by dT, the temperature coefficient α is defined by

$$\frac{dR}{R} = \alpha\,dT.$$
Here α has the dimension of an inverse temperature and can be expressed e.g. in 1/K or K.

If the temperature coefficient itself does not vary too much with temperature, a linear approximation can be used to determine the value R of a property at a temperature T, given its value R at a reference temperature T:

R(T) = R(T)(1 + αΔT), 
where ΔT is the difference between T and T. For strongly temperature-dependent α, this approximation is only useful for small temperature differences ΔT.

Temperature coefficients are specified for various applications, including electric and magnetic properties of materials as well as reactivity.