Question

If monochromatic light of wavelength 500 nm is incident on a single narrow slit 0.02 mm wide, what is the width of the central bright spot (in cm) on a screen that is 3 meters from the slit? (Hint: the width of the central bright spot is equal to the distance between the two first order minima.) 

Answer 1

The angular position of the first dark fringe is given by

Thus, the width of the central bright spot, D = 2y, is given by