In Young's double slit experiment, the two slits are 'd' distance apart. Interference pattern is observed on a screen at a distance 'D' from the slits. A dark fringe is observed on a screen directly opposite to one of the slits. The wavelength of light is
1
\(\frac{D^{2}}{2 \mathrm{~d}}\)
2
\(\frac{\mathrm{d}^{2}}{2 \mathrm{D}}\)
3
\(\frac{\mathrm{D}^{2}}{\mathrm{~d}}\)
4
\(\frac{d^{2}}{D}\)