Учебное пособие Издание второе, переработанное и дополненное Москва Астрель • act 2005 удк 811. 111 (075. 8) Ббк 81. 2 Англ-923 К48 Компьютерный дизайн обложки студии «Дикобраз»

HOMEWORK

(to be done in writing)
1. Translate into Russian.

1. 
   Providing such states existed, they could be produced by electron-positron collisions and could be detected by their characteristic decays.
   
2. 
   Supposing an antinucleus were dressed with a cloud of positrons it would be an atom of antimatter.
   
3. 
   In case a potential were applied to gas at low pressure, ionization ofthe molecules would result.
   
4. 
   Should the neutron flux increase, the flow of coolant would increase too.
   
5. 
   Had separate pieces of p- and n-type material been placed in contact, the p-n-junction would have been produced.
   
6. 
   We would understand the operation of a transistor provided we became familiar with the mechanism of charge transitions across a junction formed between a piece of n-type semiconductor and a piece of p-type.
   
7. 
   Should the reaction proceed smoothly, the end product might increase.
   
8. 
   If it were not for the radiative capture ofthe neutron no heavier isotope ofthe bombarded element would be formed.
   
9. 
   If the Moon were one half as massive as the Earth it would be two times as far from the center of gravity as the Earth is, if it were one third as massive as the Earth, it would be three times as far, and so on.
   

2. Translate into English.

1. 
   Если бы мы проверили прибор, он бы не отказал.
   
2. 
   Если бы не он, мы бы не обнаружили эту ошибку.
   
3. 
   Если бы ее спросили об этом соединении, она не смогла бы рас­сказать о его свойствах.
   
4. 
   Если бы они знали природу этого возбуждения, они получили бы другие результаты.
   
5. 
   Если бы он был здесь, он бы сказал нам, куда поместить этот образец.
   

UNIT ELEVEN
GRAMMAR: GERUND

Forms of Gerund	Active	Passive
Indefinite	solving	being solved
Perfect	having solved	having been solved

His knowing physics well To, что он знает физику хорошо,

did not surprise us. нас не удивило.

Everybody knows of Roentgen's Всем известно, что Рентген onpe-having determined the effect делил действие Х-лучей. of X-rays.
• Sentences to be translated.

1. 
   His working at this problem was known to us.
   
2. 
   Their having obtained new data is very important.
   
3. 
   Our having been asked to make such an experiment surprised him.
   
4. 
   I heard of his having carried out that research.
   
5. 
   They spoke of the results having been achieved.
   
6. 
   Einstein's being awarded the Nobel prize in physics soon became widely known.
   

WORD AND PHRASE STUDY
due to, thanks to, because of; on account of; owing to — вследствие,

благодаря, из-за
84

V+-ment = N develop + -ment = development
Form nouns from the following verbs and translate them into Russian.

move, establish, agree, adjust, improve, excite, appoint
V+ -ive = A act + -ive = active
• Think of verbs corresponding to the following adjectives and translate them into Russian.

creative, refractive, indicative, attractive, explosive, representative, expressive

READING (11 A)

• Read the passage attentively and follow the first steps in the development of nuclear physics. Get ready to talk about the facts, hypotheses and experimental observations in the field.
FROM THE HISTORY OF MESONS AND HYPERONS

In the year 1932, a Japanese physicist, Hidekei Yukawa, suggested that the nuclear forces acting between protons and neutrons should be due to the presence of a new type of particle that serves as a "nuclear glue" holding the atomic nuclei together. According to Yukawa's theoretical consideration, the new particles must have a mass intermediate between that of protons and that of electrons, so they received the name mesons (from the Greek mesons meaning "between").

Five years after the introduction of these purely hypothetical particles for the explanation of nuclear forces, they were actually observed in cosmic rays by an American physicist, Carl Anderson. The so-called "primary cosmic rays" bombarding the atmosphere of our planet are formed by streams of extremely high-energy protons and a few other heavier positively charged nuclei that are probably accelerated by electromagnetic fields in interstellar space. The energies of these primary cosmic particles range from comparatively low values to thousands of billions of electron-volts. Colliding with the nuclei of atmospheric oxygen and nitrogen at the outer fringes of the atmosphere, these primary cosmic ray particles produce various kinds of penetrating radiations, including high-energy y-quanta and streams of negative and positive electrons; in fact, positive electrons were first discovered in cosmic rays. Observing the tracks formed by cosmic ray particles in a vertical cloud chamber placed between the poles of a strong magnet, Anderson noticed that the trajectories of some of the particles, both positively and negatively charged, were bent by a magnetic field more than would be expected in the case of fast protons but considerably less than should be the case with electrons. From the observed magnetic deflection, Anderson estimated that this new kind of particle is about 200 times heavier than an electron, in agreement with Yukawa's theoretical prediction. These particles were first called "heavy electrons", but the name was later changed to "mesons".

Later studies have shown that there are actually two kinds of mesons, heavier ones called п-mesons or pions, and lighter ones known as u-mesons. Both pions and muons can carry either a positive or negative electric charge (п⁺, л^-, u.⁺, u.), and in addition there also exist neutral pions (n°). All of these new particles, as well as the positive and negative cosmic ray electrons (e⁺, e) are genetically related to each other and form a sequence somewhat similar to the sequence of the radioactive elements. It is now established that the primary high-energy protons entering the outer fringes of the atmosphere give rise to neutral and charged pions. Neutral pions possess a very short lifetime (about 10"" sec) and, in spite of their high velocity, break up into two y-quanta:
n°-* y + y¹

before reaching the surface ofthe earth. The charged pions (both positive and negative) live somewhat longer (10⁸ sec) but still most of them break up high in the atmosphere according to the equation:
я*-* u* + neutrino

Accordingly, for the study of pions and their decay into muons photographic equipment attached to large balloons must be sent high into the stratosphere.

The mean lifetime of muons is comparatively long (10⁶ sec), and many of them reach the surface of the earth and permit themselves to be photographed in ordinary cloud chambers. Since cloud chamber equipment is too bulky and heavy to be sent up in balloons, cosmic ray researchers have developed a new method for photographing the tracks of cosmic particles at high altitudes. Instead of using the ionizing properties of fast charged particles passing through humid air, the new method is based on the fact that these particles affect the grains through which they pass when they travel through a fine­grained photographic emulsion. When the photographic plate is developed it shows dark streaks that correspond to the trajectories followed by particles. A very rare photograph of this kind showing the formation of a pion resulting from the collision of a primary cosmic ray particle with a composite nucleus and the subsequent decay of this pion into a muon and an electron is shown in the figure below.


Apart from mesons, which have a mass intermediate between those of an electron and a proton recent studies of cosmic rays have discovered particles that are heavier than protons and are known under the collective name hyperons. The study of these particles and of their interrelation with each other was, for a time, the most interesting and most important field of exploration in physics.
• Find equivalents for the following phrases.

ядерные силы, вероятно, обуславливаются наличием; в соответ­ствии с теоретическими предположениями; протоны чрезвычайно высоких энергий; межзвездное пространство; энергии колеблются от сравнительно низких величин до; проникающее излучение; и поло­жительно и отрицательно заряженные; приблизительно в 100 раз тя­желее; в соответствии с теоретическим предположением; либо поло­жительный, либо отрицательный электрический заряд; кроме того, существуют нейтральные пионы; а также электроны; ряд, несколько похожий на; несмотря на их высокую скорость; среднее время жизни; слишком громоздкое; набольших высотах; вместо использования; воз­действует на зерна; когда фотопластинку проявляют; помимо мезо­нов, соответствующих траекториям, по которым следуют частицы; пион, образующийся в результате столкновения

• Re-read the passage and supply answers to the questions.

1. 
   What problem does the passage deal with?
   
2. 
   What assumption did a Japanese physicist, Hidekei Yukawa, make in 1932?
   
3. 
   What did Yukawa try to explain?
   
4. 
   What did he assume concerning the mass of these hypothetical particles?
   
5. 
   Who observed these particles experimentally?
   
6. 
   Where did Carl Andersen observe mesons?
   
7. 
   What instruments did physicists use then for observing primary cosmic ray particles?
   
8. 
   Why were mesons first called "heavy electrons"?
   
9. 
   How many kinds of mesons were discovered later?
   
10. 
    What is the difference between n- and u.-mesons?
    
11. 
    How many types of я-mesons are there?
    
12. 
    What two particles does n° break up into before reaching the surface of the earth?
    
13. 
    What is the lifetime of a neutral pion?
    
14. 
    What particles does the breakup of л° give rise to?
    
15. 
    Why does if practically never reach the surface of the earth while many ofthe muons reach the surface of the earth?
    
16. 
    Why is cloud chamber equipment difficult to be sent up in balloons?
    
17. 
    What new method has been developed by physicists for detecting tracks of cosmic particles at high altitudes?
    
18. 
    What fact is the photographic emulsion method based on?
    

• Match the synonyms from both columns.