Topic 13

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Incandescent Lamp

The first incandescent lamp for practical use was produced in Russia in 1873 by the great Russian scientist Alexander Lodygin. In his lamp he fixed a small carbon rod of about 2 mm in diameter between two copper conductors. In order to protect the lamp from burning through, the lamp’s air had been

evacuated. Vacuum at the time being far from perfect, this first lamp was short-lived. Its life was measured in hours.

In 1890 Lodygin made his first lamps with a metal filament using metals with high melting points, such as tungsten, molybdenum and osmium.

A few years later Thomas Edison, an American inventor, improved lamps with a metal filament. He used the lamp holder, the switch and some other elements of the lighting network.

Today the filament of the incandescent lamp is twisted into a spiral. The melting point of tungsten being 3,300˚, it can be heated to 3,000˚. At this temperature, however, tungsten begins to evaporate. In order to avoid evaporation of tungsten, today lamps are filled with chemically inert gas, i.e. argon or cripton.

In a gas-filled incandescent lamp the ends of a filament are connected to the two wires passing through the bulb and attached to the metal base. One of the wires is attached to the base and the other – to the base contact insulated from the base.

Industry manufactures incandescent lamps for 220 and 127 V (for lighting networks), 50 V (for railway wagons), 12 and 6 V (for motor cars), 3.5 and 2.5 V (for pocket torches) and so on.

Exercises:

1 Read and translate the following words and word-combinations:

1.1 to fix a small carbon rod

1.2 to protect the lamp from burning through

1.3 to evacuate the lamp’s air

1.4 a short-lived lamp

1.5 a filament

1.6 the elements of the lighting network

1.7 to be twisted into a spiral

1.8 to evaporate

1.9 to avoid evaporation

1.10 tungsten

1.11 to pass through the bulb

1.12 to attach to the metal base

1.13 cripton

2 Find the English equivalents to the following words and word-combinations in the text:

2.1 лампа накаливания

2.2 медные проводники

2.3 использовать металлы с высокой температурой плавления

2.4 улучшить лампу

2.5 металлическая нить накала

2.6 производить

2.7 великий русский учёный

2.8 быть далёким от совершенства

2.9 измерять

2.10 изобретатель

2.11 ламповый патрон

2.12 переключатель

2.13 наполнять химически инертным газом

2.14 изолированный контакт

2.15 карманный фонарик

3 Match the columns:

3.1 incandescent inventor

3.2 practical point

3.3 to measure wagons

3.4 an American use

3.5 lamp gas

3.6 melting lamp

3.7 inert holder

3.8 railway in hours

4 Complete the sentences:

4.1 In his lamp Alexander Lodygin fixed ….

4.2 In order to protect the lamp from burning through, ….

4.3 The American inventor Thomas Edison ….

4.4 Tungsten begins to evaporate at the temperature ….

4.5 In order to avoid evaporation of tungsten, ….

4.6 In a gas-filled incandescent lamp the ends of a filament are ….

4.7 Industry manufactures ….

5 Pair work. Ask your group-mate to answer the following questions:

5.1 When and by whom was the first incandescent lamp produced?

5.2 Why was the first lamp short-lived?

5.3 What metals were used for the filament of the first lamps in 1890?

5.4 How did Thomas Edison improve lamps with a metal filament?

5.5 What is the form of the filament of the present incandescent lamp?

Дата добавления: 2014-12-27