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

What is sky wave propagation what are its limitations?

Important Questions on Communication System

EASY

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

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

EASY

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

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

EASY

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

For television broadcasting the frequency employed is normally in range,

EASY

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

An EM wave is propagating in a medium with a velocity

\vec{V} = V \hat{i}

. The instantaneous oscillating electric field of this em wave is along

+ y

axis. Then the direction of oscillating magnetic field of the EM wave will be along

EASY

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

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 System>Propagation of Electromagnetic Waves in Atmosphere

The waves suitable for transmission of radio signals are

MEDIUM

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

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 System>Propagation of Electromagnetic Waves in Atmosphere

Which type of communication is employed in mobile phones?

MEDIUM

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

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 System>Propagation of Electromagnetic Waves in Atmosphere

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:

MEDIUM

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

Which mode of propagation uses ionosphere to reflect the transmitted signals from the Earth ? State other two modes of propagation.

MEDIUM

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

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

)

MEDIUM

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

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 System>Propagation of Electromagnetic Waves in Atmosphere

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

EASY

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

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 System>Propagation of Electromagnetic Waves in Atmosphere

The maximum electron density in the ionosphere in the moving is $10^{10} m^{- 3}$ . At noon time, it increases to $2 \times 10^{10} m^{- 3}$ . Find the ratio of critical frequency at noon and the critical frequency in the morning.

EASY

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

Ground waves are polarised at ______ direction.

EASY

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

The maximum frequency of transmitted radio waves above which the radio waves are no longer reflected back by ionosphere is ______(N = maximum electron density of ionosphere,

g =

acceleration due to gravity)

MEDIUM

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

A radar operating at a frequency of

10 GHz

and have a power

1 kw

. It is located at a mountain top of height

500 m

. The maximum distance up to which it can detect objects located on the surface of the earth is:

MEDIUM

Physics>Modern Physics>Communication System>Propagation of Electromagnetic Waves in Atmosphere

The ground receiver in line-of-sight communication cannot receive direct waves due to

What is sky wave propagation what are its limitations?

Important Questions on Communication System

Learn and Prepare for any exam you want !