Two slits are made one millimetre apart and the screen is placed one metre away. What is the fringe separation when blue-green light of wavelength 500 nm is used?
Given:
Distance between slits(d) = 1 mm = 10-3 m
Distance from screen(D) = 1 m
Wavelength of light used(λ) = 500 nm = 5 x 10-7 m
Therefore, from results of Young’s double slit experiment,
fringe separation(β) = = 5 x 10-4 m = 0.5 mm. (Ans)