The maximum range of propagation in this mode depends on
(i) transmitted power and
(ii) frequency (less than a few MHz) of high frequencies the rate of energy dissipation of the signal increases and the signal gets attenuated over a short distance.

i) LOS: Line Of Sight communication.
ii) In this communication the space waves travel directly from transmitting antenna to receiving antenna.
iii) Frequency for LOS must be more than 40 MHz.

i) The TV signals are frequency modulated. The transmission of TV signals cannot be obtained the ground wave propagation, as such signals get absorbed by ground due to their high frequency.
ii) TV signals cannot be transmitted via skywave propagation as the ionosphere is unable to reflect radio waves of frequencies greater than 40 MHz.
iii) Therefore, the only way out for the transmission of TV signals is that receiving antenna should directly intercept the signal from the transmitting antenna.

(i) Because the transmission of signal directly from the transmitting antenna to receiving antenna called a line of sight communication.
(ii) The waves traveling directly from the transmitting antenna to the receiving antenna get blocked due to curvature of the earth.
(iii) It limits both the maximum line of sight distance between the two antennas arid also the maximum distance up to which transmission can be received.

i) Search engine: The search engine is basically a web-based service tool used to search for information on World Wide Web.
ii) Communication: It helps millions of people to connect with the use of social networking: emails, instant messaging services and social networking tools.
iii) E-Commerce: Buying and selling of goods and services, transfer of funds are done over an electronic network.

i) Weather Satellites : They are used to monitor the weather and climate of Earth. By measuring cloud mass, these satellites enable us to predict rain and dangerous storms like hurricanes, cyclones, etc.
ii) Navigation satellites : These are employed to determine the geographic location of ships, aircraft or any other object.
iii) Communication satellites: Thev are used to transmit television, radio, internet signals etc. Multiple satellites are used for long distance communication.

i) FM requires a much wider channel.
ii) FM transmitters and receivers are more complex and costly.
iii) In FM reception, less area is covered compared to AM.

i) Large decrease in noise. This leads to an increase in signal-noise ratio.
ii) The operating range is quite large.
iii) The transmission efficiency is very high as all the transmitted power is useful.
iv) FM bandwidth covers the entire frequency range which humans can hear. Due to this, FM radio has better quality compared to AM radio.

(i) Noise level is high
(ii) Low efficiency
(iii) Small operating range

Advantages of AM :
(i) Easy transmission and reception
(ii) Lesser bandwidth requirements
(iii) Low cost
Limitations of AM :
i) Noise level is high
i) Low efficiency
ii) Small operating range

(i)  It is the branch of physics incorporated with technology towards the design of circuits using transistors and microchips.
(ii) It depicts the behavior and movement of electrons in a semiconductor, vacuum, or gas.
(iii) Electronics deals with electrical circuits that involve active components such as transistors, diodes, integrated circuits, and sensors, associated with the passive components like resistors, inductors, capacitors, and transformers.

(i) In military, it is used for locating and detecting the targets.
(ii) It is used in navigation systems such as ship borne surface search, air search and missile guidance systems.
(iii) Radars are used to measure precipitation rate and wind speed in meteorological observations.
(iv) It is employed to locate and rescue people in emergency situations.

A solar cell, also known as photovoltaic cell, works on the principle of photovoltaic effect. Accordingly, the p-n junction of the solar cell generates emf when solar radiation falls on it.

(i) Indicator lamps on the front panel of the scientific and laboratory equipment.
(ii) Seven - segment displays
(iii) Traffic signals, emergency vehicle lighting etc.
(iv) Remote control of television, air conditioner etc.