Chapter 19, Problem 46A

To determine

The direction of the scratches in the fun glasses.

Explanation of Solution

Introduction:

When light passes through a small slit comparable in size to the wavelength of the light, light spreads around the edges of the slit, this phenomenon is called diffraction.

When diffracted monochromatic light from different slits undergo interference, it produces a pattern of bright and dark spots called as interference pattern. In the fun glasses, the horizontal scratches produce an up and down interference pattern. The left and right pattern is produced by vertical scratches. The other stripes are produced by scratches at $45°$ above and below the horizontal.

Conclusion:

In the fun glasses, the horizontal scratches produce an up and down interference pattern. The left and right pattern is produced by vertical scratches. The other stripes are produced by scratches at $45°$ above and below the horizontal.