IMPORTANT SHORT QUESTION ANSWERS | THE MIRACLE OF RADIO
Q.1: How does the story of the conquest of communication by electrical energy describe in three chapters?
Ans: Telegraph, telephone and radio are the three devices which describe the story of the conquest of communication by electrical in three chapters. The marvels of the first and second pale before the miracle of the third.
Q.2: What were the names of three scientists who had opened the new path of progress as communication by electricity?
Ans: The names of the three scientists who had opened the new path of progress as communication by electricity are following.
- James Clark Maxwell
- Heinrich Hertz
- Guglielmo Marconi
Q.3: What was the contribution of Maxwell, Hertz and Marconi to communication by electricity?
Ans: James Clark Maxwell prophesied wireless by discovering its principles. Heinrich Hertz discovered and demonstrated those waves which are its secret and Guglielmo Marconi invented the instrument which put these ideas to practical use.
Q.4: How did Sir Oliver Lodge and Professor Righi contribute to the progress of communication by electricity.
Ans: Sir Oliver Lodge demonstrated the possibility of sending a signal by Hertzian waves, but turned aside under the pressure of other work. Professor Righi who was Marconi’s science master experimented in the laboratory and showed young Marconi his potential.
Q.5: What characteristic of wireless waves did Oliver Heaviside reveal in his experiment?
Ans: Oliver Heaviside, the English telegraphic engineer, subsequently revealed the amazing fact that the wireless waves are thrown back to the earth from the two curious mirrors which moving in the depth of the sky hundreds of miles from the surface of the earth, act as a kind of double sounding board.
Q.6: What theory did James Clark Maxwell present about light and electricity?
Ans: James Clark Maxwell was bone in 1831. He was a brilliant scientist. He worked on the nature of light. He gave a theory which describes the electromagnetic nature of light waves. He believed that light and electricity were in some way parts of the same thing. All his work was based on mathematical calculation.
Q.7: At what speed do wireless waves move? What other waves move at this speed?
Ans: The wireless waves move at the speed of 299,792.5 kilometres per second or 186,000 miles per second. This is the speed of light. Maxwell suggested that light waves and electric waves moved at the same speed. Thus, light waves and electric waves also move at this speed.
Q.8:When and how did Heinrich Hertz prove the truth of Maxwell’s theory?
Ans: Twenty-three years after Maxwell had made this discovery. Heinrich Hertz proved the truth of Maxwell’s theory. By that time it was possible to make tests with electric currents of shorter frequency. Using these tests, he revealed that the waves of electricity behave exactly as other waves in nature do.
Q.9: Why were wireless waves once called “Hertzian waves”?
Ans: A German scientist Heinrich Hertz first time discovered the waves with sufficient strength to use them for producing any kind of signal, these were wireless waves and in honour of their discoverer, they were once called Hertzian waves.
Q.10: What had Professor Righi shown to his younger student Guglielmo Marconi?
Ans: Professor Righi who was a teacher of Guglielmo Marconi had shown to his young student that the waves of electricity pass through the earth and jump into intervening space so that their faint crackle could be heard in a receiver places some distance from the other end of the wire.
Q.11: Describe Professor Righi's experiment to show that electric force can jump into space.
Ans: In his experiment, Professor Righi places two coils of wire some distance apart from each other. In one of them, there was a gap of several centimetres and through this coil, the professor sent a charge of electricity. With a flash of electric fire, the current jumped the gap and more miraculous still, the other coil of wire lying apart received the shock sent out by the flash. Through this experiment, it was proved that electric force did not need wires to carry it from point to point but it could jump into space.
Q.12: How did young Marconi make his initial experiment?
Ans: With funds supplied by his father, young Marconi made his initial experiment across the garden of his father’s house. In his experiment, he made two poles at opposite ends of the garden. An AMorse telegraph key was placed to release and control the current, a wire with a spark gap and a telephone receiver at the other pole for receiving dots and dashes of the Morse Code. Marconi obtained the wireless waves at a distance of 1.5 kilometres. He discovered that a hill between his transmitter and receiver made no difference and the magic waves went through matter as easily as they passed through the air.
Q.13: When was Marconi make his initial experiment?
Ans: Marconi came to England and submitted his invention to the British Government in 1896. In 1897, the Marconi Telegraph Company was founded in England.
Q.14: In what years were wireless signals first transmitted over the English Channel and the Atlantic Ocean? Who was responsible for these successful experiments?
Ans: Wireless signals were first transmitted over the English Channel in A.D. 1899 and across the Atlantic Ocean in A.D. 1901. Guglielmo Marconi was responsible for both of these successful experiments.
Q.15: What facts are given in the text about the first use of wireless to bring help to a ship in distress?
Ans: In the year A.D 1903, a ship used wirelessly for the first time to send distress signals. When the liner Republic collided with another ship in the Atlantic Ocean, wireless signals were for the first time used to seek help in the distress of the ship.
Q.16: Could speech be transmitted in the early days of wireless signalling? If not, how were messages transmitted?
Ans: Speech could not be transmitted in the early days of wireless signalling. Messages were transmitted in the early days by using the Morse Code. In this method, the messages were sent and received through telegraph in the form of dots and dashed.
Q.17: During what period did sound broadcasting become generally established?
Ans: Sound broadcasting became generally established in the nineteen-twenties. In 1924, Marconi carried his invention one important step forward when he arranged a method of directing the wireless waves in a straight line, thus it was possible afterwards for the transmission and reception of wireless waves carrying sound waves. After the invention of wireless sets, the telephone and the radio music, as well as speech, could be broadcasted in the nineteen-twenties, sounbroadcastedng entire millions of homes throughout the world, as the radio was a wonderful medium of entertainment and instruction.
Q.18: In what way does television advance upon sound broadcasting?
Ans: Television broadcasting is the most advanced than sound broadcasting. In sound broadcasting, only the sounds of the programme and their presenter were sent on the radio but after the invention of television transmission, it was possible to send the pictures of the programmes and their presenter on television sets.
Q.19: When did television services become popular in the greater part of the world?
Ans: Public television services began in the nineteen-thirties but their progress was halted by the outbreak of war in 1939. After the coming of peace in 1945, television services spread and became popular over the greater part of the world.
Q.20: is a television in colour possible? If so why was it not in general use by that time?
Ans: Television colour had been made possible after some years of the black and white transmission of the pictures. But at that time, the colour television sets were very expensive than black and white television sets, thus they were not in general use. Now colour television sets have become cheaper and are being used widely throughout the world instead of black and white television sets.
Q.21: What is radar? What are the functions of radar?
Ans: A radar is a device that can locate the position of a ship or an aeroplane to within 40 metres or even less if required. During the Second World War, radar played an immensely important role. Ships equipped with radar can avoid collision in fog and darkness, for they can observe the position and movements of other ships in their vicinity and also observe very accurately and coastline that may be near. All aircraft movements near airports are directed by ground controllers who can see through radar, the position of every aircraft in the area. That is why airliners land and take off safely, without the risk of collision in darkness and bad weather.
Q.22: What use can the astronomer now make or radio?
Ans: One of the more recent and most wonderful, developments of radio arises from the discovery that stars emit radio waves. Great radio telescopes with huge aerials and discoveries that stars emit radio waves. Great radio telescopes with huge aerials and sensitive receivers pick up radio waves from stars and galaxies too remote to be seen through the largest optical telescope. The radio telescope is providing astronomers with the new and immense power to explore the vast universe around them.