Exercise 5. Match the words with their definitions: inertness an electric lamp in which the light comes from an electric discharge between two electrodes in a glass tube

Exercise 5. Match the words with their definitions:

inertness	an electric lamp in which the light comes from an electric discharge between two electrodes in a glass tube
treat	to enter or force a way into
incandescent filament	not readily reactive with other elements; forming few or no chemical compounds
gas-discharge lamp	the act or process of fusing or melting together; union
fusion	an electric light in which a filament is heated to incandescence by an electric current
heliarc welding	to subject to a process, action, or change, especially to a chemical or physical process or application
handling	to give; bestow
penetrate	a fine wire heated electrically to incandescence in an electric lamp
light bulb	a type of welding that uses helium and a tungsten electrode to create an arc across two materials
impart	the manner of treating or dealing with something

Exercise 6. Match the words in column A with their synonyms in column B and make five sentences with them:

1. handling	a) get through
2. unreactivity	b) tool
3. noble gas	c) inertness
4. impart	d) synthetically
5. penetrate	e) produce
6. artificially	f) treatment
7. instrument	g) high-energy state
8. decay	h) provide
9. excited state	i) breakdown
10. manufacture	j) inert gas

Exercise 7. Give English equivalents to the following words:

зовнішня оболонка, інертний газ, інертність, за звичайних умов, вступати у реакцію, лампа розжарювання, нитка розжарювання, електрична лампочка, люмінесцентне світло, ржавіти (роз’їдати), зберігання, обробка, побічний ефект, виробляти штучно, проникати, надавати.

Exercise 8. Fill in the gaps with a suitable word:

mixture excited emits voltage efficiency

glow coatings conductors vapor field

Gas discharge lamps

When an electric current is passed through a gas, the gas _______________(1) light. This emission is exploited in many electric lamps. Fluorescent lamps, “neon” signs, and mercury- or sodium-________________(2) lamps are common examples of this kind of electric lighting, called gas-discharge lamps. Typically, such lamps use a noble gas (argon, neon, krypton and xenon) or a ______________(3) of these gases. Most lamps are filled with additional materials, like mercury, sodium, and metal halides.

Gases at atmospheric pressure are not very good ________________(4) of electricity. Therefore, to pass a current through a gas requires a special apparatus, called a gas-discharge tube. A gas-discharge tube is usually a glass tube with two electrodes sealed through its walls. When a ______________(5) is applied to the two electrodes and the pressure of the gas in the tube is reduced, eventually a pressure is reached at which a current flows, and the gas begins to_______________(6). The identity of the gas in the tube determines the color of the glow. Neon emits a red glow, helium produces pale yellow, and argon yields blue. A range of colors spanning the visible spectrum can be produced by using colored tubing or fluorescent _______________(7) inside the tubes.

The light emitted by a gas, when an electric current flows through it, results from collisions between atoms in the gas and electrons of the current. When a voltage is applied to the two electrodes of a gas discharge tube, an electric ________________(8) is created between the electrodes. In an electric field, a free electron will accelerate away from the negative electrode and toward the positive electrode. When such an electron collides with a gas molecule in its path, it may transfer some of its energy to the gas molecule, producing a gas molecule in an _______________(9) (high-energy) state.

Gas-discharge lamps offer long life and high_________________(10), but are more complicated to manufacture. Due to their greater efficiency, gas-discharge lamps are replacing incandescent lights in many lighting applications.

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