communication and explain

HISTORY OF COMMUNICATION

1.How old people communicate in olden times?

humans were not developed, so they Speech was developed by humans around communicated through signs and gestures, 200,000 years ago and symbols were developed around 30,000 years ago Writing was developed around 7,000 years ago Blon Language

2.How Were Symbols developed over time?

The first known form of communication through symbols was through cave paintings. Then petroglyphs were developed around 10,000 BC which was 20,000 years after the first cave painting. After that, humans developed pictograms to communicate with each other Pictograms were, evolved into ideograms. Finally, writing was developed around 3200 BC.

PRINTING

1.What is printing?

RAWh help of printing press. The process of producing text and pictures, usually on paper is known as printing. Printing is generally do Ral Mpl1

2.Who was Johannes Gutenberg?

The full name of Johannes Gutenberg Johannes Gensfleisch zur Laden zum Gutenberg. He was a German, born 1398, and he invented the printing press in 1436. His invention is considered as the most important invention of modern period because helped communication on a large scale Johannes Gutenberg

3.What is offset printing ?

Offset printing is a printing technique in which the inked image is transferred from a plate to a blanket made of rubber and then to the printing surface.

RADIO

1.what is radio ?

Radio is used for transmission of signals Messages, news etc. can be sent to distant places using radio, thereby, making it an
important means of communication. A radio sends signal through electromagnetic waves

2.Who invented radio ?

Radio cannot be said to be invented by a single person as many people were involved in the making of what finally developed as
radio. However, Guglielmo Marconi is credited with inventing the radio as he was the first to send a radio signal across Atlantic from England to Newfoundland Guglielmo Marconi

3.How does a radio Works?

The sound waves enter the microphone in a radio station, which has electric current running through it. These waves travel to the control room creating vibrations in the current. The technicians in the control room send them out through the air by means of the antenna on the transmitter. Every radio station is assigned a particular channel, called the channel’s frequency. The radio in our homes on cars pick these waves and we can listen to the radio.

RADAR

1.What is a radar?

Radar is an uni that radio waves usually used to letech, aircraft’s altitude and direction or speed of objects what space tele

2.How does radar work?

A radar is typically used for the purposes • To detect the speed of an object • To detect the presence of an obey To detect something a radar turns on its and sends out radio waves, It then, turn on transmitter and turns on its receiver to listen
echo. When it hears an echo it t many to be the inventor of radar as he was the first to demonstrate the successful use of radar in 1935. However, many others contributed in the development of radar

communication and explain

PHOTOGRAPHY

1.what is photography?

The practice of creating the image, by means of recording light and any other electromagnetic radiation, either electronically, with the help chemically of an image sensor, or is called photography, Camera

2.who used the first camera?

Cameras have been used by humans since long, Chinese philosopher Mo Di and Greek Mathematicians Euclid and Aristotle have described pinhole cameras in 5th and 4th centuries BC. The first permanent photograph however was made by a French inventor Nicephore Louis Daguerre Niepce in 1825. The first image of a human was captured by Louis Daguerre in 1838. George Eastman developed the technology of films in 1884. Gabriel Lippman is the inventor of a method of reproducing colours by photography.
Gabriel Lippmann

3.How does a camera work?

A camera has a lens through which an inverted image of the
scene, which is clicked, is formed on the film. A layer of
silver bromide is coated on the film, which is called expose.
After exposing, a permanent negative of the scene is made
on the film. From this negative, photos can be obtained.

TELEPHONE

1.Who invented telephone?

Alexander Geden Alexander Graham Bell was the inventor of telephone. He was born in Edinburgh, Scotland on 3rd March 1847. He was awarded the patent for telephone on March 7, 1876. The telephone switchboard, which facilitated telephone exchanges and networks, was invented by Tivadar Puskas a Hungarian engineer.

2.How does a telephone work?

A telephone system contains a hook switch, a speaker, a microphone, a duplex coil, a ringer av a touch tone keypad and frequency generator. We speak into the microphone and listen through the speaker. The hook switch connects the phone when the handset is lifted and the duplex coller us from listening our own voice. When we speel into a phone, our sound creates vibrations which are converted into electric current This electric current, through wires, reaches the earpiece of the receiving handset, where it is converted into sound waves and this can be heard An Old Telephone the listener.

MOBILE PHONES

1.When was the first call from a mobile phone made?

The first mobile telephone call, was made on 17 June, 1946, from St. Louis , Missouri, USA. The first handheld mobile phone was
Martin Cooper invented by Martin Cooper who worked as a researcher and cutive in Motorola. The first call on a handheld mobile phone was made by Martin Cooper on April 3, 1973

2.How is an SMS Sent?

When you send an SMS from your cell phone it reaches the SMS centre, from where it is forwarded to the recipient. The first SMS was sent from a computer to a mobile phone in 1992 in UK
and the first mobile-to-mobile SMS was sent in Finland in 1993
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3.What is 3G?

3G is 3rd Generation mobile telecommunication which is a standard for mobile telecommunication. The Cell Phones services included in 3G are wide-area wireless voice telephone, mobile internet access, video calls and mobile TV.

FAX

1.What is fax?

Fax or facsimile is used to send information on paper through telephone line. It is the telephonic transmission of printed
material. A telephone is connected to a printer or some output device which prints out Alexander Bain, a Scottish inventor in 1843 the material sent. Fax machine was invented by Bidwell and Arthur Korn, Improvements were made on his design by a number of
scientists like Frederick Bakewell, Giovanni Caselli, Sho

2.How does a fax machine work?

Earlier fax machines had a rotate Fax Machine drum where a piece of paper would be attached, print facing outward They had a small photo sensor a lens and a light which was attached to an arm which faced the sheet of paper. This a moved downward over the sheet of paper as the sheet rc on the drum. The drum rotated so that the photo sensor could examine one line of the paper at a time. The photosensor would focus on 01 square inches of paper. If the of paper where the photosensor focused was black the machine would send one tone to the receiving line an area was white it would send a different tone.

TELEVISION

1.When was television invented?

The world’s first demonstration of television was made by John Logie Baird in 1926. The television that Baird displayed was a
mechanical one. In the same year a fully system was designed by Kalman Tihanyi, a Hungarian electronic scanning utilizing television John Logie Bowd engineer

2 .How does a television work?

While recording, the sound and scenes are converted into electromagnetic waves. A TV camera has a tube on whose photosensitive plate falls the image formed by the lens of the camera, After this the image is changed into electric current by scanning by a cathode ray tube. The sound is also converted Old Television into electric current by a microphone. These are called video and audio signals respectively. These electromagnetic waves are received by our television antenna which sends them to our TV sets which converts them back to scene and sound.

SATELLITES

1 .What is a Satellite?

Astronomically, anything that orbits a planet is called its satellite. They are of two linds – natural and artificial
Moon is our natural satellite. Any object that orbits our Earth and is placed into the orbit by human endeavour is called an artificial satellite. They are very important for communication. Sputnik 1 launched by Soviet Union in 1957 was the world’s first
VA Satellite artificial satellite.

2.What is COMSAT?

A communication satellite is called a COMSAT. It is placed in the orbit for the purpose of telecommunications, Sputnik 1 was the first Comsat COMSAT

3.What is the bandwidth of a satellite?

The more the number of transponders on a satellite, the more
the bandwidth of the satellite. Every service requires different bandwidth hence different number of transponders.