Question

In a single-sit Fraunhofer diffraction set-up used with light of wavelength 4000 , the distance D between the central maximum and first minimum is found to be 0.3 cm . In the same setup, if the wavelength of light used is changed to 6000 , the corresponding value of D will be _____ cm .

Answer 1

Fraunhofer diffraction due to single slit. If b is diameter of lens the minima for diffraction pattern is given as b sinθ = nλ

⇒ (distancce) ∝λ

⇒ distancce = (0.3 cm) x (6000/4000) = 0.45 cm