Normal
\[L_{M'}=L_{M}+20.log\frac{OM}{OM'}\Rightarrow \frac{OM}{OM'} = \frac{OM}{OM-4,5}=10^{\frac{L_{M'}-L_{M}}{20}} \\\Rightarrow OM = 90.2m \]Chọn D
\[L_{M'}=L_{M}+20.log\frac{OM}{OM'}\Rightarrow \frac{OM}{OM'} = \frac{OM}{OM-4,5}=10^{\frac{L_{M'}-L_{M}}{20}} \\\Rightarrow OM = 90.2m \]
Chọn D
