# Chapter Review

### Concept Items

#### 13.1 Types of Waves

- No, water waves transfer only energy from one place to another.
- Yes, water waves transfer water from one place to another.

- the lowermost position of a wave
- the uppermost position of a wave
- the final position of a wave
- the initial position of the wave

Give an example of longitudinal waves.

- light waves
- water waves in a lake
- sound waves in air
- seismic waves in Earth’s surface

- the properties of the material through which it travels
- the shape of the material through which it travels
- the size of the material through which it travels
- the color of the material through which it travels

#### 13.2 Wave Properties: Speed, Amplitude, Frequency, and Period

- The amplitude of a transverse wave is measured along the direction of propagation.
- The amplitude and the wavelength of a transverse wave are measured along the direction of propagation.
- The wavelength of a transverse wave is measured along the direction of propagation.
- The displacement of the particles of the medium in a transverse wave is measured along the direction of propagation.

- compressional waves
- P-waves
- longitudinal waves
- S-waves

- the time that a wave takes to complete a half cycle
- the time that a wave takes to complete one cycle
- the time that a wave takes to complete two cycles
- the time that a wave takes to complete four cycles

- Its frequency decreases.
- Its frequency increases.
- Its frequency remains the same.

#### 13.3 Wave Interaction: Superposition and Interference

- True
- False

- Sound is louder in parts of the room where the density is greatest. Sound is softer in parts of the room where density is smallest.
- Sound is louder in parts of the room where the density is smallest. Sound is softer in parts of the room where density is greatest.
- Sound is louder in parts of the room where constructive interference occurs and softer in parts where destructive interference occurs.
- Sound is louder in parts of the room where destructive interference occurs and softer in parts where constructive interference occurs.

- The frequency depends on the propagation speed and the density of the string.
- The frequency depends on the propagation speed and the length of the string.
- The frequency depends on the density and the length of the string.
- The frequency depends on the propagation speed, the density, and the length of the string.

Is the following statement true or false? Refraction is useful in fiber optic cables for transmitting signals.

- False
- True

- Refraction is the phenomenon in which waves change their path of propagation at the interface of two media with different densities.
- Refraction is the phenomenon in which waves change their path of propagation at the interface of two media with the same density.
- Refraction is the phenomenon in which waves become non-periodic at the boundary of two media with different densities.
- Refraction is the phenomenon in which waves become non-periodic at the boundary of two media with the same density.

### Critical Thinking Items

#### 13.1 Types of Waves

Give an example of a wave that propagates only through a solid.

- Light wave
- Sound wave
- Seismic wave
- Surface wave

Can mechanical waves be periodic waves?

- No, mechanical waves cannot be periodic waves.
- Yes, mechanical waves can be periodic.

- The density of the medium varies with every cycle.
- The mass of the medium varies with every cycle.
- The resistivity of the medium varies with every cycle.
- The volume of the medium varies with every cycle.

- L-wave
- P-wave
- S-wave
- R-wave

#### 13.2 Wave Properties: Speed, Amplitude, Frequency, and Period

If the horizontal distance, that is, the distance in the direction of propagation, between a crest and the adjacent trough of a sine wave is 1 m , what is the wavelength of the wave?

- 0.5 m
- 1 m
- 2 m
- 4 m

- The wavelength difference between P-waves and S-waves is used to measure the distance to the epicenter.
- The time difference between P-waves and S-waves is used to measure the distance to the epicenter.
- The frequency difference between P-waves and S-waves is used to measure the distance to the epicenter.
- The phase difference between P-waves and S-waves is used to measure the distance to the epicenter.

Two identical waves superimpose in pure constructive interference. What is the height of the resultant wave if the amplitude of each of the waves is 1 m?

- 1 m
- 2 m
- 3 m
- 4 m

#### 13.3 Wave Interaction: Superposition and Interference

- $$\frac{X}{2}$$
- $X$
- $2X$
- ${X}^{2}$

- Seismic waves
- Pulse wave
- Standing waves
- Electromagnetic waves

- Conductivity
- Opacity
- Ductility
- Density

What is added together when two waves superimpose?

- Amplitudes
- Wavelengths
- Velocities

### Problems

#### 13.2 Wave Properties: Speed, Amplitude, Frequency, and Period

If a seagull sitting in water bobs up and down once every 2 seconds and the distance between two crests of the water wave is 3 m, what is the velocity of the wave?

- 1.5 m/s
- 3 m/s
- 6 m/s
- 12 m/s

A boat in the trough of a wave takes 3 seconds to reach the highest point of the wave. The velocity of the wave is 5 m/s. What is its wavelength?

- 0.83 m
- 15 m
- 30 m
- 180 m

### Performance Task

#### 13.3 Wave Interaction: Superposition and Interference

Ocean waves repeatedly crash against beaches and coasts. Their energy can lead to erosion and collapse of land. Scientists and engineers need to study how waves interact with beaches in order to assess threats to coastal communities and construct breakwater systems.

In this task, you will construct a wave tank and fill it with water. Simulate a beach by placing sand at one end. Create waves by moving a piece of wood or plastic up and down in the water. Measure or estimate the wavelength, period, frequency, and amplitude of the wave, and observe the effect of the wave on the sand. Produce waves of different amplitudes and frequencies, and record your observations each time. Use mathematical representations to demonstrate the relationships between different wave properties. Change the position of the sand to create a steeper beach and record your observations. Give a qualitative analysis of the effects of the waves on the beach. What kind of wave causes the most damage? At what height, wavelength, and frequency do waves *break*? How does the steepness of the beach affect the waves?