d
\({\text{I}} = {{\text{I}}_{\text{0}}}\,{e^{ - \mu x}}\)  અને આપેલ 

\(\frac{{\text{I}}}{{{{\text{I}}_{\text{0}}}}} = \frac{{36.8}}{{100}}\)

\(\frac{I}{{{I_0}}} = {e^{ - \mu x}} = \frac{{36.8}}{{100}}( \approx \,37\% )\)

\( \Rightarrow \,\,{e^{\mu x}} = \frac{{1000}}{{368}} = 2.71 = {e^1}\)

\( \Rightarrow \,\mu x = 1\,\, \)

\(\Rightarrow \,\,\mu  = \frac{1}{\lambda } = \frac{1}{{5 \times {{10}^{ - 3}}m}}\)

\( \Rightarrow \,\,\mu  = 200\,{m^{ - 1}}\)