part 2

Question 1

it is the reduction in power density with distance is equivalent to a power loss

Answer 1

wave attenuation

Question 2

free space is a vacuum, so (no loss, there is loss) of energy as a wave propagates through it.

Answer 2

no loss

Question 3

because the attenuation is due to the spherical spreading of the wave, it is sometimes called _________.

Answer 3

space attenuation

Question 4

it is generally expressed in terms of common logarithm of the power density ratio.

Answer 4

wave attenuation

Question 5

as an electromagnetic wave passes through the atmosphere, it interchanges energy with free electrons and ions. this type of reduction of power is called _______.

Answer 5

absorption loss

Question 6

which statement is correct

a. the lesser the particle density, the greater the possibility of collissions and the greater the absorption.
b. the lesser the particle density, the lesser the possibilty of collisions and the greater the absorption.
c. the greater the particle density, the greater the possibility of collisions and the greater the absorption.
d. the greater the particle density, the greater the possibility of collisions and the lesser the absorption.

Answer 6

c. the greater the particle density, the greater the possibility of collisions and the greater the absorption.

Question 7

it is the reduction in power density due to non free-space propagation

Answer 7

absorption

Question 8

it is the reduction in power density due to inverse square law presumes free-space propagation

Answer 8

wave attenuation

Question 9

______ causes severe absorption at microwave frequencies.

Answer 9

precipitation

Question 10

reflection : bouncing :: diffraction : _______

Answer 10

scattering

Question 11

refraction : bending :: interference : ____________

Answer 11

colliding

Question 12

it is sometimes referred to as the bending of the radio-wave path. however, ray does not actually bend.

Answer 12

refraction

Question 13

it is actually the changing of direction of an electromagnetic ray as it passes obliquely from one medium into another with different velocities of propagation.

Answer 13

electromagnetic refraction

Question 14

in refraction, the velocity of propagation at which an electromagnetic wave propagates is (inversely, directly) proportional to the density of the medium in which it is propagating.

Answer 14

inversely

Question 15

Refraction of electromagnetic waves can be expressed in
terms of refractive index of the atmosphere it is passing
through. Mathematically, it is _________. (the formula)

Answer 15

the square root of the
dielectric constant.
𝒏 = sqrt Er

Question 16

The amount of bending or refraction that occurs at the
interface of the two materials of different densities _____________.
a. depends on the refractive index of the two materials.
b. depends on the reflective index of two materials.
c. depends on the refractive index of one material.
d. depends on the reflective index of one material.

Answer 16

a. depends on the refractive index of the two materials.

Question 17

it is simply the ratio of the velocity of a light ray in FREE SPACE to the velocity of propagation of a light ray in a GIVEN MATERIAL.

Answer 17

refractive index

Question 18

refractive index can be mathematically expressed as ________

Answer 18

n = c/Vp

Question 19

the relationship between the angles and the indices of refraction is given by a formula known as _____________.

Answer 19

snell’s law

Question 20

what is the formula for snell’s law

Answer 20

n1sinθi = n2sinθr

Question 21

in the formula of snell’s law, n1 is the ___ while n2 is the __.

Answer 21

n1 = index of refraction of the initial medium
n2 = index of refraction of medium into which wave proagates

Question 22

In extreme cases, where the angle of incidence is large
the wave travels into a region of considerably lower
dielectric constant, the angle of refraction can be greater
that 90˚, so that the wave comes out of the second
medium and back into first. refraction becomes a form of reflection and this is called ________.

Answer 22

total internal reflection

Question 23

it is the angle of incidence that results in an angle of refraction of exactly 90˚

Answer 23

critical angle

Question 24

what is the given formula for critical angle

Answer 24

θc = (sin^-1)(n2/n1)

Question 25

it occurs when an incident wave strikes a boundary of two media and some or all of the incident power does not enter the second material.

Answer 25

electromagnetic reflection

Question 26

Saying all the reflected waves remain in medium 1, the
velocity of the reflected and incident waves are _______.

Answer 26

equal

Question 27

The angle of reflection equals to the angle of incidence. the reflected voltage intensities is ______ than the incident voltage field intensity.

Answer 27

less

Question 28

it is the ratio of the reflected and incident power densities

Answer 28

reflection coefficient (Γ)

Question 29

it is the portion of the total incident power that is not reflected

Answer 29

power transmission coefficient (T)

Question 30

for a perfect conductor, T=____

Answer 30

0

Question 31

it is the fraction of power that penetrates medium 2

Answer 31

absorption coefficient

Question 32

When an incident wavefront strikes an irregular surface, it
is randomly scattered in many directions. Such condition is called ______.

Answer 32

diffused reflection

Question 33

Whereas reflection from a perfectly smooth surface is called _________.

Answer 33

specular (mirrorlike) reflection

Question 34

Surface that fall between smooth and irregular is called _______.

Answer 34

semi-rough surfaces

Question 35

this states that a semi-rough surface will reflect as if it were a smooth surface whenever the cosine of angle of incidence is greater than 𝛌/8d, where d is the depth of irregularity.

Answer 35

rayleigh criterion

Question 36

it is the bending of waves around an object. it is also defiened as the modulation or redistribution of energy within a wavefront when it passes near the edge of an opaque object.

Answer 36

diffraction

Question 37

this phenomenon allows light of radio waves to propagate (peek) around corners.

Answer 37

diffraction

Question 38

he is the founder of the wave theory of light

Answer 38

christian huygens

Question 39

this states that every point on a given spherical wavefront can be considered as a secondary point source of electromagnetic waves from which the other secondary waves are radiated outward.

Answer 39

huygen’s principle

Question 40

As the wave front passes the object, the point sources of waves at the edge of the obstacle create additional spherical waves that penetrate and fill in the shadow zone. This phenomenon, sometimes called, ______.

Answer 40

knife-edge diffraction

Question 41

_________ result from the superposition of oscillations or waves of same nature and equal frequency.

Answer 41

interferences

Question 42

it is the mode of propagation wherein different waves propagated along such multiple paths interfere at the reception.

Answer 42

multipath propagation