Waves / Sound / Light

1. Waves / Sound / Light Chapter 14, 15, and 16

2. True / False • ____ 1. Destructive interference between two superimposed waves can result in a node, or point with no displacement. • ____ 2. A point on a wave completes one cycle every 5 seconds. The frequency of this wave is 1/5 seconds. • ____ 3. The period of a pendulum is directly proportional to the mass of the bob. • ____ 4. The differences in air pressure that create a sound wave are the result of differences in the velocities of air particles. • ____ 5. Sound waves will travel faster through a wooden table than through the air. • ____ 6. Because of the Doppler effect, an observer will hear a sound moving away from her as being higher in pitch.

3. True/False • ____ 7. In a sound wave, the wavelength is equivalent to the distance from a region of high pressure to the region of mean pressure. • ____ 8. Sound travels faster on a cold day than on a warm day. • ____ 9. A closed-pipe resonator is closed at both ends. • ____ 10. The fundamental frequency of a pipe is the lowest resonant frequency. • ____ 11. Light always travels in a straight line. • ____ 12. A light-year is a unit that measures time.

4. Multiple Choice • ____ 13. Which scenario would result in a rise in the pitch being observed? • A. The observer moves away from a stationary source. • B. The source moves away from a stationary observer. • C. A source moving away and an observer suddenly stops. • D. The observer and the source move in the same direction at the same speed. • ____ 14. Which describes a sound wave? • A. A sound wave travels in a vacuum. • B. A sound wave is a longitudinal wave. • C. A sound wave is an electromagnetic wave. • D. A sound wave has one constant speed.

5. Multiple Choice • ____ 15. Which type of resonator has harmonics in whole-number multiples of the fundamental? • A. closed-pipe resonators • C. strings • B. open-pipe resonators • D. both strings and open-pipe resonators •  ____ 16. Which is the purpose of resonance in musical instruments? • A. increase the pitch • C. make the sound louder • B. decrease the pitch • D. make the sound softer

6. Multiple Choice • ____ 17. Which is decreased when the string of a stringed instrument is loosened? • A. timbre • C. wavelength • B. pitch • D. loudness • ____ 18. What is the formula to find speed of light? • A. c = l/f • C. c = f/l • B. c = lf • D. l2/f

7. Multiple Choice • ____ 19. Which term describes a material that does not allow light to be transmitted? • A. translucent • C. polarized • B. transparent • D. opaque • ____ 20. Which kind of pigment reflects two primary light colors and absorbs one? • A. primary pigment • C. complementary pigments • B. secondary pigment • D. both primary and secondary pigments

8. va = 0 vp va vp = 0 va = 0 vp = 0 vp You hear an increasing pitch of an ambulance, but it is not moving. B A va C D

9. If these two waves were moving through water at the same time, what would the water look like? Wave 1 A x B Wave 2 x C D

10. What is its speed of this wave? Time (sec) 1 2 • 1/2 m/s • 2 m/s • 5 m/s • 20 m/s • Not enough information