Sol. Given, $\mathrm{D}=1 \mathrm{~m}$ $$ \begin{array}{ll} & \lambda 600 \times 10^{-9} \mathrm{~m} \\ & n=5 \\ \text { As } & y_{n \mathrm{n}}=\frac{n \lambda \mathrm{D}}{\mathrm{~d}} \\ \Rightarrow & \frac{5 \times 600 \times 10^{-9} \times 1}{\mathrm{~d}}=5 \times 10^{-2} \\ \Rightarrow & d=\frac{5 \times 600 \times 10^{-9} \times 1}{5 \times 10^{-2}}=60 \times 10^{-6} \mathrm{~m} \\ \Rightarrow & d=6 \mu \mathrm{~m} \end{array} $$