Assuming \( 1 \, \mu \text{g} \) of trace radioactive element X with a half life of \( 30 \, \text{years} \) is absorbed by a growing tree. The amount of X remaining in the tree after \( 100 \, \text{years} \) is __________ \( \times 10^{-1} \, \mu \text{g} \).
[Given \( \ln 10 = 2.303 \) ; \( \log 2 = 0.30 \)]
