A plane electromagnetic wave is propagating along the direction i ^ + j ^ 2 , with its polarization along the direction k . ^ The correct form of the magnetic field of the wave would be (here B 0 is an appropriate constant):

B 0 i ^ - j ^ 2 c o s ω t - k i ^ + j ^ 2

B 0 j ^ - i ^ 2 c o s ω t + k i ^ + j ^ 2

B 0 k ^ c o s ω t - k i ^ + j ^ 2

B 0 i ^ + j ^ 2 c o s ω t - k i ^ + j ^ 2

EASY

Earn 100

Explain the facts about the thermosphere?

Important Questions on Communication Systems

MEDIUM

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

A plane electromagnetic wave is propagating along the direction

\frac{\hat{i} + \hat{j}}{\sqrt{2}},

with its polarization along the direction

\hat{k .}

The correct form of the magnetic field of the wave would be (here

B_{0}

is an appropriate constant):

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

Long-range radio transmission is possible when the radio waves are reflected from the ionosphere. For this to happen the frequency of the radio waves must be in the range:

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

The physical sizes of the transmitter and receiver antenna in a communication system are:

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

The earth's atmosphere is divided into different layers. Out of these layers, ionosphere consists of

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

A TV transmission tower has a height of

140 m

and the height of the receiving antenna is

40 m .

What is the maximum distance upto which signals can be broadcasted from this tower in LOS (Line of Sight) mode? (Given: radius of earth

= 6.4 \times 10^{6} m) .

MEDIUM

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

The maximum line-of-sight distance undefined between the transmitting antenna of height undefined and receiving antenna of height undefined in undefined communication is undefined radius of the earth)

MEDIUM

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

In a line of sight radio communication, a distance of about

50 km

is kept between the transmitting and receiving antennas. If the height of the receiving antenna is

70 m,

then the minimum height of the transmitting antenna should be: (Radius of the Earth

= 6.4 \times 10^{6} m

)

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

For efficient transmission and reception, the height of antenna should be atleast

MEDIUM

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

In a communication system operating at wavelength

800 n m,

only one percent of source frequency is available as signal bandwidth. The number of channels accommodated for transmitting

T V

signals of band width

6 M H z

are (Take velocity of light

c = 3 \times 10^{8} m / s, h = 6.6 \times 10^{- 34} J - s

)

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

A plane electromagnetic wave of wavelength

λ

has an intensity

I

. It is propagating along the positive

Y -

direction. The allowed expressions for the electric and magnetic fields are given by:

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

The frequency suitable for beyond-the-horizon communication using sky waves is

MEDIUM

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

Choose the incorrect statement(s):

(i) Skywave communication takes place at frequency above approximately $30 MHz$ .

(ii) Amplitude modulated (AM) radio communication is mostly done by ground wave propagation.

(iii) $F$ layer of ionosphere is mostly responsible for skywave propagation.

(iv) Bandwidth required for transmission of video signal is generally more than audio signal.

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

100 m

long antenna is mounted on a

500 m

tall building. The complex can become a transmission tower for waves with

λ

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

An antenna uses electromagnetic waves of frequency

5 M H z

. For proper working, the size of the antenna should be

MEDIUM

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

The radius of the Earth is

6400 km

. If the height of an antenna is

500 m

, then its range is

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

The waves used for line of sight communication are

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

The waves suitable for transmission of radio signals are

MEDIUM

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

A transmitting antenna at the top of a tower has a height $32 m$ and the height of the receiving antenna is $50 m$ . What is the maximum distance between them for satisfactory communication in line of sight (LOS) mode?

EASY

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

To double the covering range of a TV transmitting tower, its height should be multiplied by:

HARD

Physics>Modern Physics>Communication Systems>Role of Atmospheric Layers in Communication

The reflected waves from an ionosphere are ____.

Explain the facts about the thermosphere?

Important Questions on Communication Systems

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