What is the unit for the coefficient of thermal expansion?

Question

if L is in m and T is in degrees C

Answer 1

Well, if L=k*T, then k should be in m/C, so you get the right units.

Answer 2

The unit is per Kelvin (or degree C), that is, T^-1. There is no length unit because the expansion is proportional. Commonly stated in parts per million per degree C.

Answer 3

percent (change in size) per degree. This of course for restricted temperature ranges as it won't be true for all temperatures.

injanier: your length/width/height unit is parts per million, which is the same as percent times 10,000