# Is the thermal time constant simply the heat capacity divided by thermal conductivity?

My professor gave me this temperature decay data to make an exponential fit and told me that the time constant tau should be heat capacity over thermal conductivity. I'm looking at the wikipedia page and that's not what I'm seeing. I don't know if there's some caveat to when we're doing 2D simulations but I just don't see how the time constant could be exactly heat capacity over thermal conductivity.

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