Answer:
Explanation:
separation between slit d = 1.2 x 10⁻⁴ m
distance of screed D = 3.5 m
distance of second order right fringe
= 2λD / d where λ is wavelength of light .
2λD / d = .0375
2 x λ x 3.5 / 1.2 x 10⁻⁴ = .0375
λ = 6428 x 10⁻¹⁰ m
= 643 nm .