In a Young's double slit experiment, two slits are illuminated with a light of wavelength 800 nm. The line joining A_1 P is perpendicular to A_1 A_2…

In a Young's double slit experiment, two slits are illuminated with a light of wavelength $\displaystyle 800$ nm . The line joining $\displaystyle A_1 P$ is perpendicular to $\displaystyle A_1 A_2$ as shown in the figure. If the first minimum is detected at $\displaystyle P$, the value of slits separation 'a' will be: The distance of screen from slits $\displaystyle \mathrm{D}=5 \mathrm{~cm}$