CHAPTER 19

Question 1

A wave is a periodic vibration in
______________.

Answer 1

both space and time

Question 2

What is the source of all waves?

Answer 2

The source is something that is vibrating.

Question 3

What is meant by the period of a pendulum?

Answer 3

The time interval of a to-and-fro swing

Question 4

Which has the longer period, a short or
a long pendulum?

Answer 4

The long pendulum has the longer period.

Question 5

If the frequency of a particular wave is 20
Hz, its period is _________.

Answer 5

1/20 second

Question 6

What is the frequency of vibration of
the electron in the antenna of a station
broadcasting at 101.7 MHz on the FM
dial?

Answer 6

101.7 million vibrations per second

Question 7

How does a sine curve describe a wave?

Answer 7

A sine curve is a pictorial representation of a
wave.

Question 8

Distinguish between these different aspects of a wave: period, amplitude,
wavelength, and frequency.

Answer 8

Period is the time from one crest to the next,
amplitude is the distance from the midpoint to a crest, wavelength is the distance from one crest to the next, and frequency is the number of crests that pass per second.

Question 9

How many vibrations per second are
represented in a radio wave of 101.7
MHz?

Answer 9

101,700,000 vibrations

Question 10

How are frequency and period related to
each other?

Answer 10

Frequency and period are reciprocals.

Question 11

What travels in a wave from one location
to another is _________.

Answer 11

energy

Question 12

The vibrations along a transverse wave
move in a direction _________.

Answer 12

perpendicular to the wave

Question 13

The vibrations along a longitudinal wave
move in a direction _________.

Answer 13

along and parallel to the wave

Question 14

Sound is transmitted by alternate compressions and rarefactions of air. What
kind of wave is sound?

Answer 14

Longitudinal wave

Question 15

In one word, what is it that moves from
source to receiver in wave motion?

Answer 15

disturbance

Question 16

Does the medium in which a wave travels move with the wave?

Answer 16

No

Question 17

In what direction are the vibrations relative to the direction of wave travel in a
transverse wave?

Answer 17

At right angles to the direction of wave travel

Question 18

In what direction are the vibrations relative to the direction of wave travel in a
longitudinal wave?

Answer 18

Parallel to the direction of wave travel

Question 19

The wavelength of a transverse wave is
the distance between successive crests
(or troughs). What is the wavelength of
a longitudinal wave?

Answer 19

The wavelength is the distance between successive maximum compressions (or rarefactions).

Question 20

What happens to the frequency of the
wave if you increase the wavelength,
keeping the velocity of the wave constant?

Answer 20

The frequency decreases.

Question 21

What happens to the frequency of the
wave if you increase the wave velocity,
keeping the wavelength of the wave constant?

Answer 21

The frequency increases.

Question 22

How can you double the frequency of a
wave if you have control over both the
wavelength and the wave velocity?

Answer 22

You can either halve the wavelength, keeping
the wave speed constant; or double the wave
speed, keeping the wavelength constant

Question 23

The speed of a wave can be found by
multiplying its frequency by its _________.

Answer 23

wavelength

Question 24

While fshing on the pier you observe
that wave crests are spaced 2 meters
and are moving at about 10 m/s, what is
the frequency of this wave?

Answer 24

5 Hz

Question 25

What is the relationship among frequency, wavelength, and wave speed?

Answer 25

Wave speed is frequency multiplied by wavelength.

Question 26

Interference is a phenomenon that occurs primarily in _________.

Answer 26

all kinds of waves

Question 27

Standing waves are produced by _________.

Answer 27

interference

Question 28

Distinguish between constructive interference and destructive interference.

Answer 28

Constructive interference occurs when the crests of two waves add together. Destructive interference occurs when a crest of one wave is reduced by the trough of another.

Question 29

What kinds of waves can show interference?

Answer 29

All waves show interference

Question 30

What is a node? What is an antinode?

Answer 30

In a standing wave, a node always has zero displacement and an antinode always has maximum displacement.

Question 31

When the bug is stationary and creating waves, how does the frequency of the wave some distance away from the bug compare with the frequency of the vibration of the bug?

Answer 31

The frequency of the wave some distance away is equal to the frequency of the vibration of the bug

Question 32

When the bug that is creating waves swims in the direction of the waves, how does the speed of the wave some distance away in front of the bug compare with the speed of the wave created by a stationary bug?

Answer 32

The speed of the wave some distance away is equal to the speed of the wave due to a stationary bug.

Question 33

When the bug that is creating waves swims forward, how does the frequency of the wave some distance away in front of the bug compare with the frequency of the wave produced by a stationary bug?

Answer 33

The frequency of the wave some distance away in front of the bug is greater than the frequency produced by a stationary bug.

Question 34

When the bug that is creating waves swims forward, how does the frequency of the wave some distance away behind the bug compare with the frequency produced by a stationary bug?

Answer 34

The frequency of the wave some distance away behind the bug is less than the frequency of the wave produced by a stationary bug.

Question 35

When a sound source approaches a stationary listener, the listener experiences an increase in sound _________.

Answer 35

frequency

Question 36

When a light source is moving away from the observer, what happens to the observed light? (There may be more than one correct answer.) Check all that apply. A. The frequency increases. B. The frequency decreases . C. The frequency remains constant. D. The wavelength increases.

Answer 36

The frequency decreases & The wavelength increases

Question 37

In the Doppler efect, does frequency change? Does wave speed change?

Answer 37

Only frequency changes.

Question 38

Can the Doppler efect be observed with longitudinal waves or with transverse waves?

Answer 38

Both

Question 39

What is meant by a blue shift and a red shift for light?

Answer 39

An approaching source has increased light frequency - a blue shift. A receding source has a decreasing frequency - a red shift.