Answer
$\frac{3}{2}$
Work Step by Step
We know that $\log_ab=c\Leftrightarrow a^c=b$ and $\ln b=c\Leftrightarrow e^c=b$.
Also, $\log_a a^x=x$ and $\log_a b^x=x\log_a b$
Hence here: $\log\sqrt{1000}=\log{(10^3)^{\frac{1}{2}}}=\log{10^{\frac{3}{2}}}=\frac{3}{2}\log10=\frac{3}{2}\cdot1=\frac{3}{2}$