Unit 7 Test Review

Unit 7 Test Review:

Waves and Sound

Waves

• waves transfer energy. not matter

• pulse wave: single disturbance

• continuous wave: oscillation produces waves on a regular bases

• standing wave: the reflection of the wave makes it appear like the wave doesn't move

• particles move in the same direction as energy of the wave

• compressions rarefactions

• move faster in more dense media

• cannot travel in space

• sound is a longitudinal wave

Longitudinal

• particles move perpendicular to energy of wave

• Crests, troughs

• move faster with less dense media

• can travel through space

• Light is a transverse wave

Transverse

Types of Waves

​Properties of Waves

• waves reflect. they bounce off of surfaces

• waves refract. waves bend when they strike a boundary and go through a medium of a different density.

• waves diffract. waves bend around openings.

• waves interfere. waves combine with other waves to form a new wave. each wave retains its own properties.

amplitudes subtract to form a wave with a smaller amplitude than any constituent wave

SOFTER. MAY BE ZERO.

​Destructive interference

amplitudes add to form a wave with a greater amplitude than any constituent wave.

LOUDER

​Constructive interference

Principle of Superposition

Multiple Choice

This is an example of a ...

• Longitudinal Wave

• Wiggly Wave

• Transverse Wave

• Standing Wave

Multiple Choice

This is an example of a ....

• Longitudinal Wave

• Squishy Wave

• Transverse Wave

• Standing Wave

Multiple Choice

The number 3 is pointing to the ...

• Trough

• Crest

• Wavelength

• Amplitude

Multiple Choice

Red line #1 is the ...

• Trough

• Crest

• Wavelength

• Amplitude

Multiple Choice

Number 4 is pointing to the ...

• Trough

• Crest

• Wavelength

• Amplitude

Multiple Choice

Red line #2 is the ...

• Trough

• Crest

• Wavelength

• Amplitude

Multiple Choice

The length traveled in one cycle is the ...

• Wave Speed

• Frequency

• Wavelength

• Amplitude

• Period

Multiple Choice

This is an example of a ...

• Longitudinal Wave

• Wiggly Wave

• Transverse Wave

• Standing Wave

Multiple Choice

Sound waves are _______ waves.

• Transverse

• Seismic

• Longitudinal

• Slow

Multiple Choice

Sound waves travel the fastest through _______.

• Gases

• Solids

• Liquids

• Plasma

Multiple Choice

True or False: Sound waves can travel through space.

• True

• False

Multiple Choice

True or False: The speed of sound depends on the loudness of the sound.

• True

• False

Multiple Choice

The amount of energy a wave carries is the _________.

• Amplitude

• Height

• Loudness

• Volume

Multiple Choice

Human perception of sound volume

• Amplitude

• Loudness

• Intensity

• Decibel

• dβ = 10log(I/I₀)

• I₀ = 1E^-12 W/m²

​Equations

• sound level is measured in decibels

• sound level is logarithmic

• a sound level of 70 is 10 times louder than a sound level of 60

• sound levels are referential; this depends the threshold of hearing

Sound Level and Intensity

Multiple Choice

Sound intensity is measured in _____.

• Hertz

• Nanometers

• Decibels

Multiple Choice

Pitch is _____.

• How often a sound wave occurs

• How high or low a sound seems to be

• The energy behind a wave

Multiple Choice

True or False: The higher the pitch, the lower the frequency.

• True

• False

Multiple Choice

True or False: According to the Doppler Effect, if an sound source is moving TOWARDS you, the pitch should be getting higher.

• True

• False

Multiple Choice

What is the Doppler Effect?

• A change in frequency due to the relative motion of a wave source and an observer

• When a wave overlaps with another wave

• When a wave bounces off of another object

• When a wave bends due to traveling through a different medium

Multiple Choice

A car is not moving but the horn is on. You run towards the car to investigate what's going on. As you approach the car, what happens to the frequency of the sound waves from the horn?

• They increase

• They decrease

Multiple Choice

Look at the picture. Who is experiencing a higher pitched sound?

• Observer A

• Observer B

• There's no difference

Multiple Choice

Look at the picture. Who is experiencing a lower pitched sound?

• Observer A

• Observer B

• There is no difference

Multiple Choice

You are driving in a car and honk the horn at a person standing in the street. As you approach the person, what happens to the pitch of the horn according to you in the car?

• It increases

• It decreases

• It stays the same because you are in the car moving with the sound.

Multiple Choice

What can you tell about this object's motion?

• Moving to the North (up).

• Moving to the South (down). 

• Moving to the West (left). 

• Moving to the East (right). 

Multiple Choice

Points A, C, and E are showing

• nodes where constructive interference is occurring

• nodes where destructive interference is occurring

• antinodes where constructive interference is occurring

• antinodes where destructive interference is occurring

Multiple Choice

A pipe that is closed at one end and open at the other resonates at a fundamental frequency of 240 Hz. The next frequency it resonates at is most nearly.

• 80 Hz

• 120 Hz

• 480 Hz

• 720 Hz

• 960 Hz

Multiple Choice

How many wavelengths are there on a string vibrating at its fundamental frequency?

• 1/4

• 1/2

• 1

• 2

Multiple Choice

A 1.5 m string is vibrating at its fundamental frequency of 440 Hz. What is the speed of the standing wave on the string?

• 147 m/s

• 293 m/s

• 660 m/s

• 1320 m/s

Multiple Choice

The pictured tube is 1.2 meters long. What is the wavelength of the wave inside?

• .6 m

• 1.2 m

• 1.6 m

Multiple Choice

This wave is found in or on a

• String

• Bar

• Open Tube

• Closed Tube

Multiple Choice

This wave is found in/on a

• String

• Rod

• Open Tube

• Closed Tube

Multiple Choice

This string is in the

• 1st harmonic

• 2nd harmonic

• 3rd harmonic

• 4th harmonic

Multiple Choice

This closed end tube is in the

• 6th harmonic

• 7th harmonic

• 8th harmonic

• 9th harmonic

Multiple Choice

What is the frequency of the pictured wave on a string if the speed of the string wave is 1000 m/s and the length of the string is .75 meters?

• 1,667 Hz

• 3,333 Hz

• 1133 Hz

• 340 Hz

Multiple Choice

When the frequency of a wave on a string increases, what happens to the wavelength?

• The wavelength is not directly affected by the frequency of a wave.

• The wavelength increases.

• The wavelength decreases.

• More specific information is needed to form a conclusion about the wavelength.

Multiple Choice

How many wavelengths are there on a string vibrating at its fundamental frequency?

• 1/4

• 1/2

• 1

• 2

Multiple Choice

You stand on the sidewalk next to the street. A fire truck is moving towards you. The frequency of the siren on the fire truck is 600 Hz.

What should you hear?

• Frequency higher than 600 Hz

• Frequency lower than 600 Hz

• Exactly 600 Hz

• No sound, silence.

Multiple Choice

You stand on the sidewalk next to the street. A fire truck is away from you. The frequency of the siren on the fire truck is 600 Hz.

What should you hear?

• Frequency higher than 600 Hz

• Frequency lower than 600 Hz

• Exactly 600 Hz

• No sound, silence.

Multiple Choice

dB is a mathematical representation with a ____ scale

• Multiplicative

• Division

• Longitudinal

• Logarithmic

Multiple Choice

The Relative change in a sound beams intensity is measured in

• Watts/cm

• dB

• watts

• Pascals

Multiple Choice

The speed of sound at 20 degrees celcius is:

• 331 m/s

• 365 m/s

• 621 m/s

• 343 m/s

Multiple Choice

This is an example of a ....

• Longitudinal Wave

• Squishy Wave

• Transverse Wave

• Standing Wave

Multiple Choice

The number 3 is pointing to the ...

• Trough

• Crest

• Wavelength

• Amplitude

Multiple Choice

Red line #1 is the ...

• Trough

• Crest

• Wavelength

• Amplitude

Multiple Choice

Number 4 is pointing to the ...

• Trough

• Crest

• Wavelength

• Amplitude

Multiple Choice

Red line #2 is the ...

• Trough

• Crest

• Wavelength

• Amplitude

Multiple Choice

The length traveled in one cycle is the ...

• Wave Speed

• Frequency

• Wavelength

• Amplitude

• Period

Multiple Choice

The number of wave cycles in a unit of time is the ...

• Wave Speed

• Frequency

• Wavelength

• Amplitude

• Period

Multiple Choice

The time for one cycle is the ...

• Wave speed

• Frequency

• Wavelength

• Amplitude

• Period

Multiple Choice

The maximum displacement from the midpoint is the ...

• Wave speed

• Frequency

• Wavelength

• Amplitude

• Period

Multiple Choice

How fast the wave travels along the medium is the ...

• Wave speed

• Frequency

• Wavelength

• Amplitude

• Period

Multiple Choice

What is the purpose of a wave?

• To confuse people.

• To transfer energy from one point to another.

• To transfer matter from one point to another.

• To alter the medium it travels through.

Multiple Choice

The motion of the medium and the motion of the particles are parallel.

• Transverse Wave

• Longitudinal Wave

Multiple Choice

The motion of the medium and the motion of the particles are perpendicular.

• Transverse Wave

• Longitudinal Wave

Multiple Choice

Electromagnetic waves cannot travel through a medium.

• True

• False

Multiple Choice

Traveling Waves are waves that go from one place to another.

• True

• False

Multiple Choice

Which of the following is an example of a longitudinal wave?

• light

• sound

• radio

• EM

Multiple Choice

Waves with a higher frequency have a ...

• longer wavelength

• shorter wavelength

• higher amplitude

• shorter amplitude

Multiple Choice

A wave with a very long wavelength has a ...

• high frequency

• low frequency

• large amplitude

• short amplitude

Multiple Choice

A wave has a wavelength of 15m and a frequency of 10Hz. What is the wave speed?

• 1.5 m/s

• 1.5m/s²

• 150 m/s

• 150 m/s²

The end