Matematyka.pl

dzięki

A) \(\displaystyle{ R = log \frac{A}{ A_{0} }}\)

R = 5

\(\displaystyle{ A_{0} = 0,0001}\)

więc
\(\displaystyle{ 5 = log \frac{A}{0,0001}}\)

\(\displaystyle{ 5 = logA - log0,0001}\)

\(\displaystyle{ logA = 5 + log0,0001}\)

\(\displaystyle{ logA = 5 - 4 = 1}\) => A = 10 cm

B) R = 4,7 - w Polsce
R = 8,7 - na świecie

\(\displaystyle{ \begin{cases} 4,7 - 1 \\ 8,7 - x \end{cases}}\)

x = 1.85 - tyle razy słabsze