Q.
In Youngs double-slit experiment, the angular width of fringe formed on a distant screen is 0.1∘ . If wavelength of light used is 6000A˚ then spacing between the slits is:
Angular fringe width α=0.1∘ =1800.1×π =1.74×10−3rad λ=6000A˚ =6000×10−10m =6×10−7m
The angular fringe width is α−dλ
(where d is the separation between the slits) d=αλ =1.746×10−36×10−7 =3.44×10−4m