Question

Two slits spaced 0.260 mm apart are 0.990 m from a screen and illuminated by coherent light of wavelength 640 nm. the intensity at the center of the central maximum (θ=0^{∘}∘) is i_{0}. part a what is the distance on the screen from the center of the central maximum to the first minimum? express your answer to two significant figures and include the appropriate units. y = ? part b what is the distance on the screen from the center of the central maximum to the point where the intensity has fallen to i0/2? express your answer to two significant figures and include the appropriate units. y =?

Answer 1

value of ∅ is not understanding