УРОК ПЕРВЫЙ
THE MODERN THEORY OF LIGHT
In the history of the theory of light we see that two very
dif-
different models have vied * from the outset * as to which
is the true
model to be u s e d. On the one hand2, light was pictured as
a
wave motion of some sort3, and on the other as a flight **
of fast-
moving particles.
During the 19th century the former model gained* universal5
acceptance6 thanks to a remarkable7 series of developments
on
both the experimental and theoretical basis.
The wave theory of light seemed to have defeated
the particle theory when it explained the approximately
rectilinear
propagation. The theory was found by the physicists
to be adequate enough to explain all the experimental re-
results of the nineteenth century in terms of* the wave
theory.
However, early in the twentieth century a series of observa-
observations on photo-electricity gave rise* to a really
serious difficulty
for the wave theory. It was found that light could cause
atoms
to em it electrons and that, when light released an electron
from
an atom, the energy possessed by the electron very greatly
exce-
exceeded 10 that which the atom could, according to
electromagnetic-
wave theory, have received. It was at this point that the
wave
theory failed" to suggest12 an explanation. It was this
fact and
others associated13 with it that showed the wave hypo-
hypothesis to be incomplete.
A return14, at leasti5 to some extent, to the particle
theory of
light appeared to be necessary. In 1905 Einstein sug-
suggested that in order to adequately" describe these
observations,
it was necessary to assume17 that the energy of a light
beam18 is
not evenly spread over the whole beam, but is concentrated
in the
form of small particles proportional to the frequency of
light.
These localized concentrations of energy he called
"photons" or
"light quanta".
For the observation to be described in detail it
is necessary to assume that the photons corresponding19 to
light
of the wavelength all have the same energy, those of blue
light
having nearly20 twice21 the energy of the red. Photons are
propa-
propagated like particles. It is assumed that there are
usually a very
large number of them, the energy in any one photon being
very
small. Thus in most ordinary22 experiments, the energy of a
light
beam is evenly distributed M, just as M a gas exerts a very
nearly
uniform25 pressure on the surface of an ordinary vessel,
because
each molecule is very small and the number of molecules is
very
large. When the movements of an ultra-microscopic particle
are
observed the irregularities26 of the Brownian movements show
the
discontinuous27 "structure" of the gas. In a
similar way28, the
atom presents to the light' beam an area so small that it
indi-
indicates the presence29 of "molecules of light"
or photons.
Thus, on the one hand, stand all the phenomena of
interference,
diffraction and polarization which are so well described by
the
wave theory. On the other hand, modern experiment has
greatly
increased the number and range of the experiments which are
readily30 described in terms of photons. The electromagnetic
picture has no place for the photons, and the particle
theory has
no place for the wave. Yet, both are required to give a
complete
description of the phenomena.
According to the present concept light has a dualS1
character
such that it may be represented equally well by waves or by
particles. The wave and particle properties of light are
found
by modern scientists to be two different aspects
of the same thing. These two aspects are to be regarded as
complementary32 rather than antagonistic, each being correct
when dealing with the phenomena in its own domain 33: In
macro-
macroscopic effects light can be treated as a continuous
wave and in
microscopic ones the photon aspect begins to become
important.
Though there seems to be no doubt34 as to the essential
correctness of this theory we still find it difficult to
understand how these two theories can both be true. Yet, we
are forced to do so by the mass of good evidence35 which can
be
brought forward in support of each of them. The acceptance
of
this concept required a fundamental w change in our ideas.
УПРАЖНЕНИЯ
Грамматические упражнения
1. Переведите предложения, содержащие
конструкцию «инфинитив как часть
сказуемого» .Укажите возможные способы
перевода коиструкции.
Назовите глаголы — первые компоненты
сказуемого, которые помогают
опознать данную конструкцию.
Образец:
A body is said to be in motion...
Тело, как говорят, находится в движении...
Говорят, что тело находится в движении...
1. Light is thought to be...
2. The speed of these particles is found to be...
3. The rocket is known to be used...
4. These forces are believed to act...
5. The changes in the orbit are considered to be...
6. These charged particles are supposed to possess...
7. The planet is expected to have...
8. The direction of the current is assumed to be...
9. The diameter of this star is reported to be...
10. This cyclotron appears to develop...
11. The solid fuel rocket seems to be...
12. The speed of particles happens to change...
13. These conditions are likely to be found...
14. Uranium is unlikely to exist...
2. Переведите предложения, содержащие
конструкцию «инфинитив как часть
сказуемого». Обратите внимание на форму
инфинитива .
Образец:
The results are known to be used...
Результаты, как известно, используются...
The results are known to have been used...
Результаты, как известно, были использованы..,
[. The rocket is found to develop speed...
2. The rocket is found to have developed speed.,.
3. The rocket was found to develop speed...
4. The rocket has been found to develop speed..,
5. The properties of the elements are known to vary...
6. The properties of the elements are known to have
varied..,
7. This limitation appears to have been overcome,,.
8. This limitation appeared to be overcome...
3. Переведите предложения, содержащие в
составе сказуемого инфинитив.
Укажите, к какому компоненту сказуемого
следует отнести при переводе
отрицание. Обратите также внимание на перевод
группы су-
существительного с предлогом, стоящей между
первым компонентом сказуе-
сказуемого и инфинитивом.
1. The Sun is known to have a 11-year cycle of activity.
2. The proton is found to be 1840 times heavier than the
electron.
3. The speed of light in vacua is one of the fundamental
physi-
physical constants and has been found to be very close to
3.00ХЮ10
centimetres per second.
4. Sputnik II is reported to have weighed about 1120
pounds.
5. The Sun of a certain galaxy is said to have a diameter
more
than 16 times the distance from the Sun to the Earth.
6. The first Earth's satellites were expected to stay on
their
orbits for a month or two.
7. Heat was thought to be a material substance.
8. The atmosphere of Saturn is believed to be about 16,000
miles deep.
9. Billions of stars are assumed to exist in the universe.
10. Some of the meteors are supposed to have formed when
comets that passed near the Earth broke up.
4. Переведите предложения, определив
инфинитивные конструкции и функции
инфинитивов.
1. Advancement in electronic techniques appears to be
endless.
2. All forms of radiant energy have been found to travel
through space with the same speed.
3. Temperatures on the surface of Mars, which seems to be
the most comfortable place for life to exist beyond our
Earth with-
within the solar system, are also of some interest.
4. Most physicists believed in the latter half of the
nineteenth
century cathode rays to be charged particles.
5. Satellites in Earth orbits of about 600
miles or greater can
normally be expected to remain in orbit for thousands of
years.
6. The first satellite to be designed and developed in England
was Ariel 3 which was successfully put into orbit on May 5,
1967.
7. To say that an object is travelling at a speed of 20
ft/sec
(feet per second) does not describe the motion completely.
8. A day on Jupiter has been observed to be 9 Earth hours-
and 55 minutes long, the shortest of any of the planets.
9. When sound waves are directed on the diaphragm they
cause it to move backwards and forwards.
10. The choice of radioisotope to be used as the source is
determined by the thickness of the product to be measured.
Лексические упражнения
1. Переведите предложения, обращая внимание иа
то, что выделенные при.
лагательные имеют близкие значения.
1. The plane was provided with a conventional piston engine.
2. The measurement of the pressure distribution over the
sur-
surface of a model is a common type of experiment in
wind-tunnel
work.
3. Ordinary liquids are bad conductors compared to metals.
2. Переведите предложения, обращая внимание на
перевод наречий hardly,
nearly A,20), readily A,30), necessarily @).
Помните, что значения этих наречий нельзя
вывести иа основе значений
соответствующих прилагательных. Сравните
значения прилагательных и
наречий.
1. Nearly all the models which were tested proved successful.
2. Liquids are perfectly elastic, but they are so nearly
incom-
incompressible that this property is not of much practical
use.
3. The voltage will hardly remain the same during the ex-
experiment.
4. In 1918 aeroballistics as a science hardly existed.
5. Cold neutrons are useful as they penetrate most solid
materials readily.
6. Radiation in the infrared region can be readily detected
by heat it produces.
7. For the application of the computer to the solution of
engineering problems a working knowledge of differential
equa-
equations is necessarily assumed.
8. Plasmas need not necessarily be associated with high tem-
temperatures.
3. Переведите предложения, обращая внимание иа
перевод существительного
evidence A,35).
1. During the eighteenth and nineteenth centuries chemists
slowly had been accumulating evidence that all matter was
com-
composed of atoms.
2. The photographic evidence clearly indicates that approxi-
approximately 90 per cent of all visually observable meteors
are of
cometary origin.
3. The 1956 close approach of Mars brought very little new
evidence concerning the origin of geometrical patterns on
its
surface.
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