or, \(\lambda=\frac{\mathrm{d}}{2} ;\) Fringe width, \(\beta=\frac{\lambda \times \mathrm{D}}{\mathrm{d}^{\prime}}\)
\(10^{-2}=\frac{d}{2} \times \frac{50 \times 10^{-2}}{d^{\prime}}=\frac{10^{-6} \times 50 \times 10^{-2}}{2 \times d^{\prime}}\)
Therefore, slit separation distance, \(\mathrm{d}^{\prime}=25 \,\mu \mathrm{m}\)