...but, is it true that K*T = hv ? Being K Boltzmann constant...and v the frequency. Because I have seen this exercise, in which they just say that a sample A in thermal equilibrium (maybe this is the bit that I'm missing out...) absorbs light at 697cm-1, so the temperature of the sample is T = hv/k. This was done by my teacher, but I don't trust him LOL. Any ideas please? Thanks a lot!!!!