1. If someone is around a corner from you, what is the main reason you can hear him speaking but can't see him?
(a) Sound travels farther in air than light does.
(b) Sound can travel through walls, but light cannot.
(c) Sound waves have long enough wavelengths to bend around a corner; light wavelengths are too short to bend much.
(d) Sound waves reflect off walls, but light cannot.
2. When a CD is held at an angle, the reflected light contains many colors. What causes these colors?
(a) An anti-theft encoding intended to prevent copying of the CD.
(b) The different colors correspond to different data bits.
(c) Light reflected from the closely spaced grooves adds constructively for different wavelengths at different angles.
(d) It is part of the decorative label on the CD.