Answer
$10$
Work Step by Step
Recall:
$\log_a{\left(a^n\right)}=n$
Using the rule above, and knowing the natural logarithms has base $e$, gives:
\begin{align*}
\ln{\left(e^{10}\right)}&=\log_e{\left(e^{10}\right)}\\
&=10
\end{align*}