From a single slit, first diffraction minima is obtained at 30º for a light of 6500 Aº wavelength. Then what will be the width of the slit?

3250 Aº  1.3 μm 5.4 X \( { 10}^{-4 } \) 1.2 X \( { 10}^{-2 } \)

1.3 μm

Use :  θ = λ/w w is the width.