I. Memorize the pronunciation of the following words and word combinations:

Bulb, filament, tungsten, voltage, violently, discharge, incandescence, oxygen, purposes, suitable.

II. Find the Ukrainian equivalents for the following English word combinations.

a) bulb, wife, filament, human hair, in spite of, constantly, to glow, oxygen, incandescence, vacuum.

b) сяяти, кисень, нитка напруги, катод, людське волосся, електрична лампочка, постійно, дріт, вакуум, проте, напруга.

III. Read and translate text: “how electric light is produced”

If you look at the electric light bulb, you will see two heavy metal wires coming up from the base with a very fine wire between their ends. This fine wire is called “a filament” and is made of the metal tungsten. Tungsten is conductor of electricity that is its atoms allow some of electrons to escape. We say these are free electrons in the tungsten wire. When the filament is connected to a generator, the electrons try to push through the filament. The filament is hardly thicker than a human hair, however, and not vеry many electrons are able to get through easily. In spite of that many electrons are trying to push through because the electronic pressure, or voltage is pushing them. As a result the filament becomes crowded with the electrons, the electrons are constantly pushing the atoms of tungsten. So, the atoms are moving violently. Fast atomic or molecular movement is heat. Thus, the tungsten filament becomes hot and begins to glow, or to give off light. The electric light is produced either by the filament lamp or by the electric discharge lamp. The brightness of the filament lamp results from heating its filament to incandescence.

It is the bulb that keeps the air out the filament is enclosed in the glass bulb from which all the air is evacuated or into which an inert gas is introduced to prevent the filament from burning out. If oxygen is penetrating into the bulb it will be combining with the hot tungsten, in other words, the tungsten filament will burn out at once.

The first electric arc lamp for practical application was the carbon lamp. The English scientist Davy began demonstrating it first in London in 1810 but there were no machines working at the problem of the carbon arc lamps at his time. We owe much to him for his useful invention that is applied now for practical purposes.

The filament is hardly thicker than a human hair. Carbon was not a good material for filaments, however, and research workers were working hard for a long time to produce suitable filaments. At present tungsten is used for filament as it is the best metal for this purpose. Only after creating a vacuum in the bulb the problem of practical use of the electric light lamp was solved. Still now the scientists are conduction new researches to improve lamps.

Post-text exercises:

I. Fill in the blanks with following words:

metal, conductor, to push, the atoms, molecular, filament, carbon.

1. A filament is made a... tungsten. 2. Tungsten is a... of electricity. 3. When the filament is connected to a generator, the electrons try ... though the filament. 4. The electrons are constantly pushing... of tugsten. 5. Fast atomic or... movement is heat. 6. The tungsten.. will burn out at once. 7.... was not a good material for filaments.