Chapter 9 Open Book Quiz (Science)

Identify a mechanical wave that is also a longitudinal wave.

A sound wave is a longitudinal and mechanical wave.

Identify a wave that speeds up when it passes from air to water as well as one that slows down.

A sound wave speeds up as it passes from air to water. A light wave slows down as it passes from air to water.

When a longitudinal wave travels through a medium, in which direction does the matter in the medium move?

Along the same direction the wave travels.

What is half of the vertical distance from the crest to the trough of a transverse wave?

Amplitude

When a transverse wave travels through a medium, which way does matter in the medium move?

At right angles to the direction in the waves travel.

Compare and contrast refraction and diffraction of waves.

Both phenomena are caused by bending of waves. Refraction is caused by waves bending because they change speed when passing from one medium to another. Diffraction is caused by waves bending around a barrier.

What is the formula for calculating wave speed?

C=lambda x f or wavelength x frequency

Sound waves open band around columns and large concert Halls. Is this a result of refraction of diffraction?

Diffraction

Which term describes the bending of a wave around an object?

Diffraction

What do waves transfer?

Energy

The period of a wave can be directly calculated from which of the following; amplitude, frequency, or wavelength.

Frequency

What can be measured in hertz?

Frequency

What is the number of waves that pass a point in a certain time period called?

Frequency

Water waves on a lake travel toward a dock with a speed of 2.0m/s and a wavelength of 0.5m. How many wave crests strike the dock each second? (Hint: frequency)

Frequency = speed/wavelength Frequency = 2/0.5 Frequency = 4Hz

Calculate the frequency of a water wave that has a wavelength of 0.5 meters and a speed of 4 m/s.

Frequency = spped/wavelength Frequency = 4/0.5 Frequency = 8Hz

Describe how the world would be different if all waves were mechanical waves.

If all waves were mechanical waves then light waves would not be able to travel through the vacuum of space. The energy from the Sun would have no way to reach the Earth. As a result, Earth would be very cold and dark.

What happens to the frequency of a wave if the period of that wave is increased?

If the period is longer, the frequency is lower.

Describe how the wavelength of a wave changes if the wave slow s down but it's frequency does not change.

If the wave slows down with no change in frequency, the wavelength decreases.

What occurs when waves overlap?

Interference

Describe how a standing wave forms and why it has nodes.

It happens when the medium is moving in the opposite direction to the wave. It can also rise in a stationary medium as a result of interference between two waves traveling in opposite directions.

If the frequency of a vibrating object decreases, how does the wavelength of the resulting wave change?

It increases

Explain why objects that are underwater seem to be closer to the surface that they actually are.

It is due to the refraction of the light rays at they travel from the water and into the air.

Describe the difference between a longitudinal wave a large amplitude and one with a small amplitude.

Large Amplitude = More energy Small Amplitude = Less energy

Describe the path that light waves take when you see your image in a mirror.

Light waves travel from a light source where some of them reflect off you. Some of those light waves that travel to the mirror where they reflect off the mirror. Some of these light waves then travel from the mirror to your eye.

Explain why it is easier to hear low frequency sounds than high frequency sounds when a large tree is between you and the sound source.

Low frequency sounds have longer wavelengths than high frequency sounds. If the wavelength longer than the tree is wide than the sound can diffract around the tree.

In a science fiction movie, a huge explosion occurs on the surface of a planet. People in a spaceship heading toward this planet see and hear the explosion. Is this realistic? Explain.

NOT realistic. Sound waves cannot travel through space.

An earthquake on the ocean floor produces a tsunami that reaches a remote island. Is the water that reaches the island the same water that was above the earthquake on the ocean floor? Explain.

No. Waves transfer energy NOT matter.

Which part of a longitudinal wave has the lowest density?

Rarefaction

What can occur when a wave passes from one medium into another?

Refraction

Identify evidence that seismic waves transfer energy without transferring matter.

Seismic waves and cause great change. Tidal waves and direct damage to building and other structures are caused by earthquakes. However, the waves move through Rock and soil. Rock and soil are not carried along with the waves.

Explain why you can hear a fire engine coming around a street corner before you can actually see it.

Sound waves have longer wavelength the light waves; therefore, they can diffract around the corners or echo off the building. Light waves cannot.

Compare the loudness of sound waves that constructively interfere with the loudness of sound waves that destructively interfere.

Sound waves will be louder where they constructively interfere and softer whey they destructively interfere.

An FM radio station broadcasts radio waves with a frequency of 96,000,000 Hertz. What is the speed of these radio waves if they have a wavelength of 3.1 meters?

Speed = (wavelength)(frequency) Speed = (3.1)(96,000,000) Speed = 297,600,000m/s

The microwaves produced inside a microwave oven have a wavelength of 12cm and a frequency of 2,500,000,000Hz. At what speed (in m/s) do the microwaves travel?

Speed = wavelength(frequency) Speed = 0.12(2,500,000,000) Speed = 300,000,000

A tuning fork vibrates at a frequency of 440Hz. The wavelength of the sound produced by the tuning fork is 0.75m. What is the speed of the wave?

Speed = wavelength/frequency Speed = 0.75/440 Speed = 0.0017m/s

Which type of wave has point, called nodes, that do not move?

Standing Wave

The average speed of sound in water is 1500 meters per second. How long would it take a sound wave to travel 9000 meters in water?

T = d/s T = 9,000/1,500 T = 6 seconds

If the amplitude of a wave changes, which also changes?

The disturbance or energy transferred by the wave.

Explain how the frequency of a wave changes when the period of the wave increases.

The frequency of a wave decreases when the period of the wave increases.

Describe the motion of a unanchored rowboat when a water wave passes. Does the wave move the boat forward.

The row boat moves up and down, as well as slightly back and forth. The row boat returns to its original position after the wave has passed.

Describe how one tuning fork's vibrations can cause another tuning fork to vibrate.

This can occur if both tuning forks are tuned to the same frequency, so they both have the same natural frequency. The vibrations of one tuning fork will cause the air around the other tuning fork to vibrate at the natural frequency of both tuning forks. The second tuning fork will absorb this energy and start to vibrate. This is called resonance.

You make a transverse wave by shaking the end of a long rope up and down. Explain how you would shake the end of the rope to make the wavelength shorter.

To make the wavelength shorter, you would increase the frequency of shakes.

When the crests of two identical waves meet, what is the amplitude of the resulting wave?

Twice the amplitude of each wave.

Describe the objects are materials that vibrated to produce 3 of the sounds that you have heard today.

Vocal cords, bell, car engine.

What happens when two waves pass through each other?

Wave interference

Calculate the wavelength of a wave traveling on a spring when the wave travels at 0.2m/s and has a frequency of 0.5Hz.

Wavelength = speed/frequency Wavelength = 0.2/0.5 Wavelength = 0.4m

Explain why water waves traveling toward a swimmer on a float do not move the float forward along the way.

While the water waves do travel toward the swimmer, the water itself only moves up and down.

Contrast how you would move a spring to make a transverse wave with how you would move a spring to make a longitudinal wave.

You would move the spring up and down or side-to-side to create a transverse wave. You would move the spring forward and backward to create compressions for a longitudinal matter.