Прочтите и переведите текст; найдите описание модели электромагнитного аппарата, используйте слова small, inch-long, copper wire в ответе

1. Faraday knew from his long study of electricity that magnetism should be able to produce a current, as well as vice versa. In spite of his various failures, the idea of producing a current directly by magnetic action remained firm in his thoughts. One of his friends said later how at this period of his long life Faraday used to carry about with him in his pocket a small rough model of electro-magnetic apparatus. This consisted simply of an inch-long straight iron rod, or core, with some turns of copper wire wound round it.

2. The basic idea he had in mind was this: if an electric current in a wire can produce a magnetic effect, why should not a magnet near a conducting wire produce an electric current? It was really a simple reversal of Oersted's 1820 discovery.

3. On August 29 1831, Michael Faraday made his first successful experiment. By a happy choice, he decided to work not with a straight bar оr even a horseshoe magnet, but with a ring. He made a soft iron ring, nearly an inch thick and six inches in external diameter. On opposite sides of this ring he had wound long coils of fine copper wire, separating each turn by string and each layer by calico, for insulation purposes. The ends of the left-hand coil he connected to his galvanometer three feet away, while the ends of the right-hand coil were connected up to a battery. When he switched on the battery circuit, there was immediately a slight reaction on the magnetic needle connected to the other coil. In his own words: "It oscillated and settled at last in its original position". On switching off the battery again, there was "a deflection of the needle", but while the so-called voltaic current was flowing through the wire there was no reaction on the galvanometer. This happened many times: each time the battery current came on, the needle linked to the opposite, unconnected coil deflected and then came to rest; each time the circuit was broken, the same effect was noticed.

4. Faraday was a little disappointed, having expected to get a positive deflection of the needle all the time his battery current was switched on. Instead he got it only when the magnetic field in the iron ring was changing – either switching on or switching off.

5. Nevertheless, he had produced electricity through magnetism, which had never been done before. There was no connection between the left-hand coil on the ring and the right-hand coil fed from the battery, nor was there any leakage of current from one side to the other. Yet as the galvanometer needle showed, electricity, however weak, had flowed momentarily each time through the left-hand coil. It was new electricity where none existed before, and it had been produced, or induced, by electromagnetism.

Примечания

1. remained firm in his thoughts – не оставляла его мыслей

2. by a happy choice – по счастливой случайности

3. three feet away – расположенный на расстоянии трех футов

2.3.3 В чем был убежден Фарадей на основе своего длительного и глубокого изучения электричества? Используйте слова magnetism, produce, current

2.3.4 В каком абзаце текста говорится о главной мысли, которая не давала покоя Фарадею?

2.3.5 Используйте следующие слова для описания устройства, которое использовал Фарадей для своего эксперимента: a ring, inch, in external diameter, to wind, coil, copper, wire, to separate, turn, string, layer, insulation, to connect, ends, battery

Date: 2016-02-19; view: 1052; Нарушение авторских прав