Question
33. Angular width of central maximum in the Fraunhoffer diffraction pattern of a slit is measured. The slit is illuminated by light of wavelength 6000 A.� when the slit is illuminated by the light of another wavelength then the angular width decreases by 30%. Calculate the wavelegth for this light. The same dedcrease in the angular width of central maximum is obtained when the original apparatus is immersed in the liquid. Find the refractive index of the liquid?