Physics - Wave Optics Question with Solution | TestHub

In Young's double slit experiment, light of wavelength $\lambda$ passes through the double-slit and forms interference fringes on a screen $1.2\mathrm{m}$ away. If the difference between 3 rd order maximum and 3 rd order minimum is $0.18\mathrm{cm}$ and the slits are $0.02\mathrm{cm}$ apart, then $\lambda$ is