Question

Consider the following related to single-slit diffraction.

a. Does ray optics give a correct prediction for single-slit diffraction?

b. Suppose you have two slits, A&B. Slit A has width 0.12mm and Slit B has width 0.24mm. If you shine a laser through each slit, how would your observations of single-slit diffraction be different for each of the slits?

c. If the laser you use has a wavelength of 650nm, then how many wavelengths of the laser are equivalent to the widths of slits 1 and 2?

d. What is similar about the patterns created by each slit?

e. What is different about the patterns created by each slit?

Answer 1

a. The ray optics does not provide a correct prediction for single slit prediction because there must not be a diffraction pattern if we consider the light to be a ray.

b. The two slits would produce a single slit diffraction but since the width of fringes is inversely proportional to the slit width, the fringes would be closely spaced for Slit B than slit A.

c. For slit A. width is 0.12 mm. Thus .

Now, if slit width is 0.24 nm.

d. Both the slits would produce a diffraction pattern which would consists of bright fringes separated by dark fringes.

e. The diffraction pattern produced by both the slits would be different in terms of the fringe width. The fringes would be closely spaced for the slit which have larger slit width.