Answer:
Explanation:
Slit distance d = .25 x 10⁻³ m .
Distance of screen D = 60 x 10⁻² m
Distance between first and fifth minimum = 5.5 x 10⁻³ m .
There will be four bright fringes between first and 5 th minimum so
distance between them = 4 x λ D / d where λ is the wavelength of light .
Substituting the values
4 x λ x 60 x 10⁻² m / .25 x 10⁻³ m = 5.5 x 10⁻³ m
4 x λ x 60 x 10⁻² m = .25 x 10⁻³ m x 5.5 x 10⁻³ m = 1.375 x 10⁻⁶ m
λ = .005729 x 10⁻⁴
= 572.9 x 10⁻⁹ m
= 572.9 nm .
