Question

how to ln value 0.693

Answer 1

use a calculator

Answer 2

are you asking what is x in
\[ \ln(x) = 0.693 \]
?
to "undo" a log, make both sides the exponent of e (e=2.71828...)
\[ e^{ \ln(x)} = e^{0.693} \]
\[ x = e^{0.693}\]