Wave Optics

In a Young's double slit experiment, two slits are illuminated with a light of wavelength \(800 \mathrm{~nm}\). The line joining \(A_{1} P\) is perpendicular to \(A_{1} A_{2}\) as shown in the figure. If the first minimum is detected at \(P\), the value of slits separation 'a' will be:

The distance of screen from slits D = 5 cm