Physical Science Final Review- Chapter 10: Waves and Sound

If the frequency of a particular wave is 20 Hz, its period is A) 1/20 second. B) 20 seconds. C) more than 20 seconds. D) none of the above.

A) 1/20 second

Compressions and rarefactions normally travel... A) in the same direction in a wave B) in opposite directions in a wave C) at right angles to the wave D) none of the above

A) in the same direction in a wave

A sound source of high frequency emits a high... A) pitch. B) amplitude. C) speed. D) all of the above E) none of the above

A) pitch

Which of the following is a longitudinal wave? A) sound B) radio C) light D) all of the above E) none of the above

A) sound

A bass fiddle is louder than a harp because of its... A) sounding board B) lower pitch C) thicker strings D) all of the above E) none of the above

A) sounding board

Compared with a dry road, seeing is difficult when driving at night on a wet road. Why? A) Wet surface is smooth with less diffuse reflection, part of which would otherwise reach the driver's eyes. B) Wet road usually means a wet windshield. C) Wet road usually means more vapor in the air. D) There is no reason—that's just the way it is.

A) wet surface is smooth with less diffuse reflection, part of which would otherwise reach the driver's eyes

The range of human hearing is about... A) 40 Hz - 40,000 Hz. B) 20 Hz- 20,000 Hz C) 10 Hz - 10,000 Hz. D) all of the above, depending on the person

B) 20 Hz to 20,000 Hz

When a firetruck approaches you, the.. A) speed of its sound increases B) frequency of sound increases C) wavelength of its sound increases D) all increase

B) frequency of sound increases

A wave barrier is produced in water when the speed of an object... A) is less than the speed of waves in water B) matches the speed of waves in water C) exceeds the speed of waves in water D) none of the above

B) matches the speed of waves in water

When we consider the time taken for a pendulum to swing to and fro we're talking about the pendulum's... A) frequency B) period C) amplitude D) wavelength

B) period

The vibrations along a transverse wave move in a direction... A) along the wave B) perpendicular to the wave C) both of the above D) neither of the above

B) perpendicular to the wave

Reverberation is a case of... A) sound interference. B) re-echoed sound. C) forced vibrations. D) resonance. E) none of the above

B) re-echoed sound

The speed of a sound wave in air depends on... A) its wavelength B) the air temperature C) its frequency D) all of the above E) none of the above

B) the air temperature

When sound travels faster at ground level than higher in the air, sound tends to bend... A) downward B) upward C) neither

B) upward

In Europe an electric razor completes 50 vibrations in 1 s. The frequency of these vibrations is... A) 1/50 Hz with a period of 50 s B) 1/50 Hz with a period of 1/50 s C) 50 Hz with a period of 1/50 s D) 50 Hz with a period of 50 s

C) 50 Hz with a period of 1/50s

A wave is a vibration in... A) time B) space C) both D) neither

C) both

The natural frequency of an object depends on its... A) size and shape B) elasticity C) both D) neither

C) both

The Doppler effect occurs for... A) sound B) light C) both A and B D) neither A nor B

C) both A and B

Interference is a property of... A) sound B) light C) both of these D) neither of these

C) both of these

A Doppler effect occurs when a source of sound moves... A) toward you B) away from you C) either D) neither

C) either

The distance between adjacent peaks in the direction of travel for a transverse wave is its... A) frequency B) period C) wavelength D) amplitude

C) wavelength

The medium in which a wave travels... A) moves along with the wave B) reflects the wave C) inhibits the wave D) transmits the wave

D) transmits the wave

Infrasonic waves

Frequency < 20 Hz

Ultrasonic waves

Frequency > 20,000 Hz

Resonance

Occurs whenever successive impulses are applied to a vibrating object in rhythm with its natural frequency Causes a dramatic increase in amplitude (sound waves get louder)

Speed of Sound

Sound travels at 340 m/s in air at 20* C For each increase of 1* C above 0* C, speed of sound increases by 0.6 m/s speed of sound in air = 340 m/s speed of sound in warm air > 340 m/s speed of sound in water - four times the speed in air speed of sound in steel = 15 times speed in air

Diffuse Reflection

When sound or light is incident on a rough surface, it is reflected in many directions

Longitudinal Wave

a wave that causes vibration along or parallel to their direction to its own motion EX: sound waves, seismic P-waves (earthquakes and explosions)

Transverse Wave

a wave that causes vibration in the medium in a perpendicular direction to its own motion EX: electromagnetic waves (radio and light waves) and seismic S-waves

Interference

combined effect of two or more overlapping waves Property of all wave motion

Period

defined as the time it takes for a complete vibration Unit: any unit of time, usually the second Period = 1/frequency

Wave speed

describes how fast a disturbance moves through a medium Related to the frequency and wavelength of a wave

Amplitude

distance from the midpoint to crest or trough

Wavelength

distance from the top of one crest to the top of the next crest, or distance between successive identical parts of the wave

Pitch

frequency of the sound high frequency = high pitch low frequency = low pitch

Crests

high points of the wave

Troughs

low points of the wave

Frequency

number of to-and-fro vibrations in a given time unit: 1 vibration per second = 1 Hertz A higher frequency means an increased rate of energy transfer and shorter wavelengths Frequency = 1/period

Natural Frequency

own unique frequency of set of frequency Depends on elasticity, size and shape

Shock wave

pattern of overlapping spheres that form a cone from objects traveling faster than the speed of sound The shockwave actually consists of two cones. - A high pressure cone with its apex at the bow - A low pressure cone with its apex at the tail. - A graph of the air pressure at ground level between the cone takes the shape of the letter N.

Beats

periodic variations in the loudness of sound due to interference Occurs with any kind of wave Provides a comparison of frequencies

Reflection

process in which sound encountering a surface is returned AKA echo Multiple reflections called reverberations Angle of incidence = angle of reflection

Sound waves

produced by vibrations made up of compressions and rarefactions spread from the source through the air

Forced vibration

setting up of vibrations in an object by a vibrating force Example: factory floor vibration caused by running of heavy machinery

Refraction

the bending of a wave due to a change in the medium and/or speed of the wave

Doppler Effect

the change in frequency as measured by an observer due to the motion of the source or listener

Destructive Interference

the crest of one wave overlaps the trough of the other, they cancel each other out

Constructive Interference

the crests are overlapped with each other, increased amplitude

Bow Wave

the wave pattern made by a bug swimming at wave speed. Idealized wave pattern made by a bug swimmer faster than wave speed. Overlap occurs only when the bug swims faster than wave speed

3 reasons sound waves refract

waves travel at different speeds waves are affected by uneven winds when air near the ground is warmer than air above

Vibration

wiggle in time The source of all waves described by frequency- how frequently a vibratory motion occurs

Wave

wiggle in time and space transports energy described by frequency, speed, amplitude, and wavelength