Answer the questions:

1. What two different theories of light do you know?

2. Which theory gained universal acceptance in the 19^th century?

3. Why did serious difficulty arise for the wave theory in the 20^th century?

4. What did Einstein suggest in 1905?

5. What was the conclusion of the scientists?

Exercises

I. Translate the sentences paying attention to the meanings of the verbs in bold type.

gain

1. An atom may gain one or more electrons.

2. Using this type of engine one can gain much in terms of effectiveness.

3. A rocket with a constant thrust continually gains in speed.

4. This book is for anyone who wants to gain, with the least difficulty, a complete understanding of the fundamentals of radio and electronics.

fail

5. All the attempts to explain the processes of emission and absorption through the electromagnetic theory of light have failed.

6. The classical laws of both mechanics and electricity fail to predict the behavior of atoms.

7. Helicopters were used to transport men and supplies to the forward line when ground transport failed.

8. Some scientists failed to realize the role of mathematics in science.

9. The author did not fail to make reference to all the previous works concerning the subject of his article.

suggest

10. The step-rocket for space travel was suggested by Tsiolkovsky.

11. The scientist suggested a new method of measuring cosmic ray intensities.

12. Rutherford suggested that the positive charge of electricity was concentrated in the nucleus of the atom.

13. Ampere suggested that the origin of all magnetism lay in small circulating currents associated with each atom.

14. The book "Analytical Mechanics for Engineers", as its name suggests, presents those principles of mechanics that are essential for the study of engineering.

assume

16. It is ordinary assumed that uncharged objects contain equal amounts of positive and negative electricity.

17. The air in the "standard" atmosphere is assumed to be perfectly dry.

18. A liquid is unable to maintain a particular shape and it immediately assumes the shape of the container.

19. Rockets may assume a great variety of forms and sizes.

II. Translate the sentences choosing the right variant.

In terms of: 1. В одиницях, у величинах;

2. На підставі, з точки зору;

1. Acceleration may be expressed in terms of distance, time and velocity.

2. The force of gravity is measured in terms of weight.

3. Jet engines are usually expressed in terms of the thrust they produce.

4. In order to express the magnitude of a force, some standard force must be selected as a unit in terms of which other forces must be expressed.

5. The basic concepts of thermodynamics are most easily understood in terms of simple experiments.

give rise (to smth.) — викликати, бути причиною, створювати

6. Most of the primary cosmic rays entering our atmosphere cause nuclear collisions and give rise to secondary particles.

7. The fission of uranium atoms gives rise to a wide range of new isotopes.

8. The use of rockets for solar research has given rise to the development of new types of solar instruments.