Propagation of Electromagnetic Waves

Which mode of propagation is used by short wave broadcast services having frequency range from a few MHz upto 30 MHz?

Suppose for a given antenna the maximum distance it can transmit signal is $32 \mathrm{km}$, then calculate the height at which antenna is placed.

What could be the maximum distance up to which the signal transmitted from an antenna at a height of $100 \mathrm{m}$ can be received?

What do you understand by range of a signal?

The electron density of the ionosphere is $4\times {10}^{12} {\mathrm{m}}^{-3}$. Calculate the critical frequency of radio waves in sky wave propagation.

What is a skip zone?

What is the skip distance$?$

A TV tower has a height of $80 \mathrm{m}$. What is the maximum distance and area (in ${\mathrm{km}}^2$ ) upto which this TV transmission can be received? Take radius of the earth as $6.4\times {10}^6 \mathrm{m}$ (take value of $\mathrm{\pi }=3.14$):

A TV tower has a height of $200 \mathrm{m}$. How much population is covered by the TV broadcast if the average population density around the tower is $1200 \mathrm{k}{\mathrm{m}}^{-2}$ (radius of the earth$=6.37\times {10}^6$ m)

A TV tower has a height of 100 m. How much population is covered by the TV broadcast if the average population density around the tower is $100 \mathrm{k}{\mathrm{m}}^{-2}$ (radius of the earth$=6.37\times {10}^6$ m)

A layer of ionosphere does not reflect waves with frequencies greater than 10 MHz; then maximum electron density in this layer is 

Ground waves are polarised in ______ direction.

The sky wave propagation is suitable for radio-waves of frequency

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

The electric field of an electromagnetic wave travelling through vacuum is given by the equation$E=E_0\sin (kx-\omega t)$. The quantity that is independent of wavelength is

The frequency range of $3 \mathrm{MHz}$to $30 \mathrm{MHz}$ is used for

Which type of communication is employed in mobile phones-

In space communication, the sound waves can be sent from one place to another

A TV tower has a height of 100 m. How much population is covered by the TV broadcast if the average population density around the tower is $1000 \mathrm{k}{\mathrm{m}}^{-2}$ (radius of the earth$=6.37\times {10}^6$ m)