4. Answer the questions on the text:

1. Who was George Ohm?

2. In what sphere of science was he famous?

3. What discoveries of George Ohm do you know/?

4. What research did George Ohm conduct?

5. What was the main concept of his famous law?

6. What is an electromotive force?

7. How is the potential difference between two points defined?

8. Do you think, is Ohm’s law of great importance or not? Explain why.

5. Put the verbs given in brackets in Continuous Active or Passive (Present, Past, Future)

1. Using Ohm’s law is of great importance because of its generally (to apply) to so many electrical phenomena.

2. An interesting research in the field of electronics constantly (to do) at our University now.

3. The scientists (to discuss) some questions of international relations nowadays.

4. Our country (to develop) all branches of industry now.

5. Ohm (to start) his law having no reliable voltmeters, ammeters, or batteries.

6. They (to organize) this kind of work at their laboratory from 5 to 7 o’clock yesterday.

7. Now solar energy research groups and its usage (to study) by a lot of research groups.

8. Our factories (to produce) all kinds of machines and equipment nowadays.

6. Change the following into the Past Continuous and Future Continuous. Translate these sentences

1. The scientists are maintaining constant temperature during the experiment.

2. Ukrainian builders are carrying out a huge housing program.

3. They are constantly to thinking about their experiment.

4. That professor is preparing a scientific report now.

5. The question about the new invention is being discussed at a special meeting.

6. The students are translating the paper at present moment.

7. The new engine is being tested in the laboratory.

8. A new research is being carried out successfully.

7. Point out the verbs in Continuous Active and Passive in every line:

1. a) bits b) was biting c)biting;

2. a) blows b)is blowing c)shall be blowing;

3. a) forgave b)will be forgiven c)is forgiving;

4. a) are fought b)is being fought c)will fight;

5. a) was broken b)broke c)is breaking;

6. a) watched b)are watched c)is watching;

7. a) flew b)were flown c)are flying;

8. a) wrote b)have written c)is writing.

8. Divide the verbs into two groups: Active and Passive Voice. Translate them

was born, strove, decided, went, was sent, was returned, became, was engaged, was doing, is being produced, was being built, wrote, founded, created, are named, is known, is shown, is put, is giving, are taken, were started, was taught, are being made

9. Speak about Ohm’s law

UNIT17. SEMICONDUCTORS

1. Memorize the following words:

semiconductor - напівпровідник

to link – зв'язувати, з'єднувати

to involve – включати в себе, залучати

ability - здатність

extraordinary – видатний, незвичайний

humidity – вологість

value – цінність, важливість

abnormal – ненормальний, аномальний

to perceive – усвідомлювати, розуміти

to attach – надавати, прикріпляти

2. Translate the following international words without a dictionary

Academician, thermo-electric, system, theoretical, scientist, physics, television, deformation, mechanism, photoelectric, data, temperature, thermal, electric, special, sphere, technology, problem

3. Read and translate the text:

The success of physics of semiconductors is linked with the name of the famous scientist – Academician A.F. Yoffe. He began to concentrate on physics of semiconductors in the early thirties. He had a wide range of scientific interests. His research involved light waves, the mechanism of plastic deformation, the photoelectric effect.

At that time little importance had been attached to the ability of semiconductors to absorb heat and produce electricity was extremely low. And then Academician Yoffe declared that the research into semiconductors had points of theoretical interest and held out great promise for commercial development. This sounded quite fantastic at that time.

It didn’t take the scientist too much time to prove his point. Semiconducting elements with an improved efficiency were developed shortly before World War II. The data compiled by Yoffe as a result of his fundamental research enabled him to formulate a systematic theory of semiconductors which paved the way for their large scale commercial utilization. Semiconductors have found their way to radio-receivers and television sets, and became essential in measuring techniques thanks to their being extraordinary sensitive to light, temperature and atmospheric humidity. However, all this was only the beginning in this new branch of physics. Yoffe was after problems that were more complex and of greater value.

In studying the theory of semiconductors Yoffe had in mind the direct conversion of solar energy into electricity. He though it abnormal that of the energy so generously sent by the sun only a small fraction was used by man, only a quarter of one per cent. And even making use of this fraction involved tremendous difficulties: the mining of coal, the construction of turbines and other equipment. Scientists working in this field were looking for a way of converting solar energy and making it serve people directly. Yoffe perceived such a possibility in semiconducting thermal elements in which an electric current is induced by ordinary light. A solar battery 100 km long could provide enough power to meet the world’s demands.

Yoffe noticed that semiconducting elements may serve equally well as sources of heat and cold. Semiconductor refrigerators have been developed.

A long series of experiments and preliminary theoretical studies enabled the scientists to find thermo-electric systems with an extraordinary high efficiency, and develop a kind of a miniature power plant. Electric stations of this type are now being used.