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Magnetic field. Fig. 2. Faraday's experiment. With the electro-magnet. Phrases & word combinations to the text. Exercises
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Magnetic field
Fig. 2. Faraday's experiment
with the electro-magnet
In America, Joseph Henry, professor of mathematics and natural science, also starting from Oersted's and Sturgeon's observations, used the action of the electric current upon a magnet to build the first primitive electric motor in 1829. At about the same time, Georg Simon Ohm, a German school-teacher found the important law of electric resistance: that the amount of current in a wire circuit decreases with the length of the wire, which acts as resistance. Ohm's excellent research work remained almost unnoticed during his life time, and he died before his name was accepted as tha of the unit of electrical resistance.
PHRASES & WORD COMBINATIONS TO THE TEXT
1. now and then – время от времени
EXERCISES
TASK 1. Answer the questions:
1. What was happened in 1819? _______________________________________
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2. What was it that Oersted discovered? _________________________________
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3. Did his discovery make any impression on physicists all over Europe and America? _______________________________________________________
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4. How did an electrically charged conductor work? ________________________
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5. Did he find that any piece of soft iron could be turned into a temporary magnet by putting it in the centre of a coil of insulated wire and making an electric current flow through the coil? _______________________________________
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6. Who built the first large electro-magnet? ______________________________
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7. What did Faraday discover? _________________________________________
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8. Was Faraday’s experiment with the electro-magnet succesful? ______________
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9. What is the important law of electric resistance? _________________________
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10. Who used the action of the electric current upon a magnet to build the first primitive electric motor in 1829? _____________________________________
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TASK 2. Translate the passage from “ What Faraday had discovered …” to” …of the unit of electrical resistance ” in the written form.
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TASK 3. Fill in the blanks with words and word combinations from the text:
Prompted by the ___________ of Andre-Marie Ampere, the __________ whose name has become a household word as the unit of the ___________, the Englishman Sturgeon experimented with ordinary, non-magnetized iron. He found that any _______ iron could be turned into a __________by putting it in the centre of a coil of _________ and making an ___________ flow through the coil. As soon and as long as the current was turned on the __________, but it ceased to be a magnet when there was no more current.
TASK 4. Continue the sentenses according to the text:
1. One day in 1819 a Danish physicist___________________________________
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2. Demonstrating a galvanic battery_____________________________________
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3. Nothing more than that_____________________________________________
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4. Prompted by the research work of Andre-Marie Ampere__________________
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5. Every time he went for a walk_______________________________________
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6. A stationary magnet does not________________________________________
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7. This phenomenon, confirms the basic fact______________________________
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8. Thus Faraday demonstrated quite_____________________________________
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9. Meanwhile, fundamental research_____________________________________
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10. Georg Simon Ohm, a German school-teacher found the important law of electric resistance: _________________________________________________
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TASK 5. Translate into English:
Христиан Эрстед, читал лекции в Университете. Демонстрируя гальваническую батарею, он держал провод, идущий из нее, когда тот вдруг выскользнул из его руки и упал на стол прямо на морской компас, который случайно оказался там. Когда он поднялся провод, то он обратил внимание, к свому удивлению, что игла компаса больше не указывала север, а качнулась совершенно в другую сторону.
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TASK 6. Give your own opinion on the text
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TEXT 5
THE NATURE OF THE ATOM
There is one source of energy, however, which owes nothing to 
the heat and light of the sun; nor can it be harnessed by a chemical process. It is the energy of the atomic nucleus.
Today we know that atoms are neither unchangeable nor indivisable. It may be sufficient to recall that Marie and Pierre Curie, by their discovery of radium, in 1898, made the whole theory of the indivisible atom crumble, 
because here was an element which disintegrated and sent out rays, consisting of particles much smaller than the atom.
Another discovery, made three years earlier, seemed to point in the same direction: that of the X-rays by Professor Wilhelm Konrad Rontgen at the University of Bavaria.
These and other phenomena and discoveries around the turn of the century 
were deeply disturbing for the physicists, and they saw that the whole traditional concept of the structure of matter had to be completely revised. Wnen, as early as 1905, Albert Einstein published his Special Theory of Relativity, in which he declared that matter could be converted into energy — very little matter into very great energy — there was a storm of protest in the scientific world. But little by little the evidence that he was right accumulated, and within a few years an entirely new picture of the atom emerged from the studies and laboratories of scientists in many countries. From that evidence Lord Rutherford, the New Zealand-born scientist, and his young Danish assistant, Niels Bohr, developed by 1911 their revolutionary theory of what the atom was really like. The electrons, which have next to no mass and weight, 
are negatively charged; in fact, they are the carriers of electricity in all our electric wires and appliances. Normally there are as many positive protons in the nucleus as there are electrons revolving around it, so that their charges cancel each other out and the atom as a whole is electrically neutral.
Hydrogen, for instance, being the lightest; and simplest element, has only one of each; uranium, the heaviest element occurring in Nature, has 92. Theoretically, we could change lead into gold, as the alchemists dreamed of doing, by removing three protons and electrons from a few billion lead atoms, which have 82 of each, then we would get gold atoms with 79 protons and electron each. However, the knocking-off process would be much more expensive than the gold we would get.
The neutrons, which are present in the atoms of many elements, are of particular importance in the utilization of atomic energy. Most elements are mixtures of ordinary atoms and so-called isotopes: the isotope atoms have more, or fewer, neutrons than the ordinary atoms. An isotope differs from the ordinary form of the element only in weight, but chemically it behaves in exactly the same way. Water, for instance, is a mixture of ordinary molecules of hydrogen and oxygen atoms and of 'heavy' ones. The heavy hydrogen atom has an extra neutron in its nucleus. Uranium, on the other hand, 
has an isotope whose nucleus contains fewer neutrons than the ordinary element. This isotope — atomic weight: 235; atomic weight of ordinary uranium: 238 – has a very special significance in nuclear physics because it is, like many other heavy-element isotopes, 'unstable'.
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Curies discovered in radium an unstable nucleus is one that is likely to break up into the nucleus of another element. Professor Otto Hahn found in Berlin in 1938 that when uranium atoms are bombarded with neutrons they split up in a process which he called 'fission' (a term used in biology for the way in which some cells divide to form new ones). The 92 protons of the uranium nucleus split up into barium, which has 56, and krypton, a gas with 26 protons. Frederic Joliot-Curie, the son-in-law of Marie Curie, proved some months later that in this fission process some neutrons from the uranium nucleus were liberated; they flew off, and some struck other nuclei, which in turn broke up, liberating still more neutrons. Enrico Fermi, an Italian who liad gone to America to escape life under fascism, developed the theory of what would happen if a sufficiently large piece of unstable uranium broke up in this way — there would be a 'chain reaction': the free neutrons would be bombarding the nuclei with such intensity that in no time at all 
the whole lump of uranium would disintegrate.
This was the theory that led, within the short space of four years, to the first atom bombs. On Monday, 6 August 1945, while cheerful crowds in England enjoyed their first holiday after the end of the war in Europe, one such bomb was dropped on the town of Hiroshima in Japan. It killed or injured nearly 200, 000 people. Three days later another bomb was dropped on Nagasaki, with 65, 000 victims. The centres of both cities were completely destroyed.
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