1. Red 2. Green 3. Blue 4. Cyan 5. White Part of the soap bubble looks yellow in sunlight. What color is being cancelled by wave interference? 1. Red 2. Green 3. Blue 4. Cyan 5. White Ch 29-1

1. Red 2. Green 3. Blue 4. Cyan 5. White Part of the soap bubble looks yellow in sunlight. What color is being cancelled by wave interference? 1. Red 2. Green 3. Blue 4. Cyan 5. White Ch 29-1 Answer: 3 The part of the bubble that looks yellow is deficient in its complementary color, blue.

Three sets of Polaroids, one atop the other, are shown above Three sets of Polaroids, one atop the other, are shown above. In each set the polarization axes of two Polaroids are at 90° to each other, and a third is at 45° to the two. Which set(s) will pass light where the three overlap? Ch 29-2 1. A 2. B 3. C

Three sets of Polaroids, one atop the other, are shown above Three sets of Polaroids, one atop the other, are shown above. In each set the polarization axes of two Polaroids are at 90° to each other, and a third is at 45° to the two. Which set(s) will pass light where the three overlap? Ch 29-2 Answer: 2 Only set B will pass light where all Polaroids overlap, for the axis of each Polaroid is not at 90° to the one next to it. The vector diagram shows that half the light gets through the first Polaroid, shown by the vertical vector, and 0.707 of this gets through the second Polaroid because it is at 45° (not 90°), and in turn 0.707 of this gets through the third. In set A all light is blocked by the back pair of Polaroids because they are at 90° to each other. Likewise with the front pair of Polaroids in set C. 1. A 2. B 3. C

The lines on the lenses of the eyeglasses indicate the plane of polarization through which light can pass. Which pair of glasses has the plane of polarization in the best orientation for reducing road glare while driving? 1. 2. 3. Ch 29-3

The lines on the lenses of the eyeglasses indicate the plane of polarization through which light can pass. Which pair of glasses has the plane of polarization in the best orientation for reducing road glare while driving? 1. 2. 3. Ch 29-3 Answer: 2 Glasses 2 are best for reducing road glare because most of the light that composes glare from nonmetallic surfaces is polarized in the same plane as the surface—horizontal. Glasses 1 will pass horizontally polarized light and will be terrible for driving. Glasses 3 are for the person who wants all bets covered. When the glare is from horizontal surfaces, the left eye should be closed; when the glare is from vertical surfaces, flagpoles and the like, the right eye should be closed. Since most glare is from horizontal surfaces, and driving is best with both eyes, select 2!