In an experiment where you light a long filament vertical light bulb. If you look at it from several meters away through a vertical slit cut in a 3 X 5 card, you will see a lovely fringe system. Explain what's happening.

Multiple choice:

1. Light linearly polarized in the plane-of-incidence impinges on the surface of a glass plate in air at Brewser's angle. The transmitted beam is:

(a) nonexistent

(b) linearly polarized in the plane-of-incidence

(c) linearly polarized perpendicular to the plane-of-incidence

(d) partially polarized

(e) none of these. Explain your choice.

2. For two sources to be coherent, it is both necessary and sufficient that each:

(a) be exactly in step, that is, in phase

(b) have exactly the same amplitude

(c) be monochromatic

(d) be linearly polarized

(e) none of these. Explain your choice.

Problem:

1. Four ideal linear polarizers are stacked one behind the other with the transmission axes of the first vertical, the second at 30 deg, the third at 60 deg, and the fourth at 90 deg. What fraction of the incident unpolarized light emerges?

2. A narrow beam of natural light shines onto a flat sheet of polystyrene (np = 1.59) 1.00 cm thick, and it is found that the reflected beam is linearly polarized. At what angle will the transmitted beam leave the sheet on its bottom side?