The light of wavelength 6328 Å is incident on a slit of width 0.2 mm perpendicularly, the angular width of central maxima will be

The angular half width of the central maxima is given by sin⁡θ=λa⇒θ=6328×10−100.2×10−3rad=6328×10−10×800.2×10−3×π degree =0.18∘ Total width of central maxima =2θ=0.36∘