Module 10—Introduction to Wave Propagation, Transmission Lines, and Antennas

Question 1

Warning

Answer 1

AN OPERATING PROCEDURE, PRACTICE, OR CONDITION, ETC., WHICH MAY
RESULT IN INJURY OR DEATH IF NOT CAREFULLY OBSERVED OR
FOLLOWED.

Question 2

Caution

Answer 2

AN OPERATING PROCEDURE, PRACTICE, OR CONDITION, ETC., WHICH MAY
RESULT IN DAMAGE TO EQUIPMENT IF NOT CAREFULLY OBSERVED OR
FOLLOWED.

Question 3

Note

Answer 3

An operating procedure, practice, or condition, etc., which is essential to emphasize

Question 4

Propagation (definition)

Answer 4

movement through a medium (such as light rays)

Question 5

Radio waves are

Answer 5

radiant energy (such as light or heat)

Question 6

Radio waves travel at

Answer 6

the speed of light

Question 7

A wave can be defined as

Answer 7

DISTURBANCE (sound, light, radio waves) that moves through a MEDIUM (air, water, vacuum).

Question 8

Wave motion can be defined as

Answer 8

a recurring disturbance advancing through space with or without the use of a physical medium. Wave motion, therefore, is a means of moving or transferring energy from one point to another point.

Question 9

Transverse Wave Motion (definition)

Answer 9

The up and down motion at right angles to the
outward motion of waves (ex. in the case of a stone being dropped in water, the water is not actually being moved outward by the motion of waves, but up
and down as the waves move outward).

Question 10

Wavelength (definition)

Answer 10

the distance from the crest of one wave to the crest of

the next, or between any two similar points on adjacent waves.

Question 11

Water waves are known as

Answer 11

transverse waves

Question 12

The amplitude of a transverse wave is

Answer 12

half the distance measured vertically from the crest to the trough

Question 13

Types of transverse waves

Answer 13

water, radio, light, heat (sound is longitudinal)

Question 14

radio, light and heat waves are examples of

Answer 14

transverse waves

Question 15

Sound waves are known as

Answer 15

longitudinal waves

Question 16

Sound waves travel

Answer 16

back and forth in the same direction as the wave motion. Therefore, longitudinal waves are waves in which the disturbance takes place in the direction of propagation.

Question 17

Longitudinal waves are sometimes called

Answer 17

Compression waves

Question 18

Compression waves are usually called

Answer 18

Longitudinal waves

Question 19

They’re called compression waves because

Answer 19

air is elastic, and when the material (ex. tuning fork tines) moves outward, the air in front of it is compressed so that it’s momentary pressure is raised above that at other points in the surrounding air. (air in this case is the medium.)

Question 20

rarefied (definition)

Answer 20

something made less dense. or expanded. the air pressure is lowered below that of the other points in the surrounding medium. (the air.) (the opposite of a compression wave, such as when a tuning fork tine moves inward rather than out)

Question 21

a medium (definition)

Answer 21

the vehicle or means though which the wave travels from one point to the next

Question 22

a source is

Answer 22

the object producing the waves

Question 23

an object responding to the waves is called

Answer 23

a detector or a reciever

Question 24

a detector (definition)

Answer 24

an object responding to the waves

Question 25

a receiver (definition)

Answer 25

an object responding to the waves

Question 26

the three requirements for a wave to be propagated

Answer 26

source, medium and detector/receiver | with the exception of electromagnetic waves, which don't require a medium

Question 27

reference line (definition)

Answer 27

a rest position or point of zero displacement

Question 28

point of zero displacement (definition)

Answer 28

a rest position or reference line

Question 29

positive alternation (definition)

Answer 29

the portion of a wave above the reference line

Question 30

negative alternation (definition)

Answer 30

the portion of a wave beneath the reference line

Question 31

the crest (definition)

Answer 31

the peak of the positive alternation of a wave

Question 32

the trough (definition)

Answer 32

the peak of the negative alternation of a wave

Question 33

wavelength (definition)

Answer 33

the distance in space occupied by one cycle of a radio wave at any given instant

Question 34

λ (lambda) is the symbol for

Answer 34

wavelength

Question 35

L is the symbol for

Answer 35

inductance

Question 36

I is the symbol for

Answer 36

dimensional length

Question 37

frequency (definition)

Answer 37

the number of cycles (vibrations) of a wave train in a unit of time

Question 38

cps (definition)

Answer 38

cycles per second (also known as Hertz)

Question 39

hertz (definition)

Answer 39

cycles per second

Question 40

the two types of wave motion

Answer 40

transverse and longitudinal

Question 41

velocity of propagation (definition)

Answer 41

the rate at which the disturbance travels through the medium, or the velocity with which the crest of the wave moves along

Question 42

the higher the frequency

Answer 42

the greater the number of compressions and expansions per unit of time

Question 43

period (definition)

Answer 43

the time in which one complete vibratory cycle of events occurs

Question 44

f is the symbol for

Answer 44

frequency

Question 45

t is the symbol for

Answer 45

time

Question 46

proper units of length

Answer 46

if the velocity (expressed in feet per second) is divided by the frequency (expressed in cycles per second, or Hz), the wavelength is given in feet per cycle. If the metric system is used and the velocity (expressed in meters per second) is divided by the frequency (expressed in cycles per second), the wavelength is given in meters per cycle. Be sure to express both the wavelength and the frequency in the same units.

Question 47

wave velocity (definition)

Answer 47

the speed with which a wave train passes a fixed point

Question 48

reflection wave (definition)

Answer 48

wave that is neither transmitted nor absorbed, but are reflected from the surface of the medium they encounter

Question 49

incident wave (definition)

Answer 49

a wave directed toward the surface of the mirror

Question 50

reflected wave (definition)

Answer 50

the wave when it bounces off the mirror

Question 51

the normal (definition)

Answer 51

the perpendicular, or the point at which the incident wave strikes the mirror's surface

Question 52

the angle of incidence (definition)

Answer 52

the angle between the incident wave and the normal

Question 53

the angle of reflection (definition)

Answer 53

the angle between the reflected wave and the normal

Question 54

law of reflection

Answer 54

the angle of incidence is equal to the angle of reflection

Question 55

transfer of energy is greatest when

Answer 55

the wave is nearly parallel to the reflecting surface

Question 56

transfer of energy is least when

Answer 56

the incident wave is perpendicular to the surface

Question 57

refraction (definition)

Answer 57

when the wave changes direction due to passing into another medium that has a different velocity of propagation

Question 58

the angle of refraction (definition)

Answer 58

the angle between the normal and the path of the wave through the second medium

Question 59

if the wave passes from a less dense medium to a more dense medium

Answer 59

it is bent toward the | normal, and the angle of refraction (r) is less than the angle of incidence (i)

Question 60

if the wave passes from a more dense to a less dense medium

Answer 60

it is bent away from the normal, and the angle of refraction (r1) is greater than the angle of incidence (i1)

Question 61

diffraction (definition)

Answer 61

the bending of the wave path when the wave meets an obstruction

Question 62

am band radio waves are

Answer 62

lower frequency

Question 63

fm band radio waves are

Answer 63

higher frequency

Question 64

``` doppler effect (definition) assumes the frequency at the source is constant ```

Answer 64

the apparent change in frequency or pitch when a sound source moves either toward or away from the listener, or the listener moves away from the source