Question

The distance between the first and fifth minima of a single-slit pattern is 0.35 mm with the screen 40 cm away from the slit, using light having a wavelength of 560 nm. (a) Calculate the diffraction angle θ of the first minimum. (b) Find the width of the slit.

Answer 1

(a) Let the angle of diffraction be θ5 for the fifth minimum, and the corresponding distance on the screen from the central maximum be d5. Thus,

where θ = diffraction angle of the first minimum

d = distance of the first minimum on the screen from the central maximum

D = distance of the screen from the slit.

So, we have