Waves and Sound Review Sheet --Physics
Chapters 14 and 15
For your test you should be able to define the following terms:
Wave
Medium
Disturbance
Wave Pulse
Standing Wave
Reflection
Echo
Frequency
Period
Amplitude
Wavelength
Crest
Trough
Resonance
Beats
Doppler Effect
Decibel
Longitudinal Wave
Transverse Wave
Constructive Interference
Destructive Interference
Node
Antinode
You should be able to label the anatomy of a wave (i.e. crest, trough, amplitude, and wavelength)
You should be able to determine how a wave pulse will be reflected when it reaches a free or fixed end.
You should know what happens when a wave moves from one medium to another.
You should know how waves interfere.
You should be able to solve the following problems:
1. Find the frequency of a pendulum with a period of 7 s.
2. 14 complete cycles of a wave pass you in 8 seconds. Determine the period and frequency of the
wave.
3. Determine an equation for force in terms of work and distance.
4. The wave speed in a guitar string is 265 m/s. The length of the string is 63 cm. You pluck the center
by pulling it up and letting it go. Pulses move in both directions and are reflected off the ends of the
string. How many seconds does it take for the pulse to return to the center?
5. A state trooper’s car sends out a radar signal at a frequency of 10.5 GHz (1GHz = 1X109 Hz). The speed
of the wave is 3x108 m/s (the speed of light). What is the wavelength of the wave?
6. A sound wave of wavelength 0.7m and velocity 330 m/s is produced for 0.5s. What is the frequency
of the wave?
7. Draw the 5th harmonic of a closed pipe and determine the frequency in terms of its length.
8. An open pipe produces a sound wave of frequency 250Hz when vibrating at its 4th harmonic. What is
the length of the pipe? (The speed of sound is 331 m/s)
9. What would the length of the pipe be from the question above if the temperature were 25C?
10. A string of length 2.2 m sets up a standing wave of wavelength 2/7L. How many nodes does the
string have and what is the wavelength?
11. A closed pipe of length 1.5 m resonates at its fundamental frequency. The speed of sound in the
pipe is 331 m/s. What is the frequency of the wave?
12. A dolphin located in seawater at a temperature of 18C emits a sound directed toward the bottom
of the ocean 150m below. Let the velocity of sound in water be 1530 m/s. How much time passes
before the dolphin hears the echo?
13. How much louder is a 60dB sound than a 20dB sound?
14. How much louder is a 120 dB sound than a 50dB sound?
15. What is the length of a pendulum on Earth that has a period of 4.5 sec?