Unit 17

I. Выпишите из Прил. 1 значения следующих слов, запомните их:

target (n), range (n), reflect (v), surface (n), initial (a), distant (a), object (n), last (v), fraction (a), accurately (adv), aircraft (n), capable (a), enable (v).

II. Выпишите из Прил. 2 значения следующих терминов, запомните их:

wavelength

III. Сгруппируйте антонимы, переведите их:

1. Distant (a), find (v), particular (a), last (v), fast (a), reflect (v), short (a), early (a), charge (v), place (v), accurate (a), capable (a), discover (v).

2. Inaccurate (a), ordinary (a), near (a), slow (a), discharge (v), long (a), incapable (a), displace (v),cover (v), late (a), attract (v), lose (v), stop (v).

IV. Прочтите текст, заполните пропуски подходящими по cмыслу предлогами и союзами из списка, данного ниже. Переведите текст.

Radar (Radio Detection and Ranging) detects objects or “targets” and determines their distance (range) and direction (azimuth). Radar's basic principles are... old... radio itself.... Heinrich Hertz... Marconi experimented... reflected ultra-short waves, the “radio echoes” used... radar. Hertz demonstrated... electric waves could be reflected from plane (плоский) or curved (изогнутый) metal surface in accordance with the same laws... apply to light waves. By measuring the wavelength and the frequencies... the impulses Hertz calculated their velocity and found it to be the same... that of light –... an electromagnetic radiation.

Nothing much was done... those early experiments, and it was only in 1890 when Nikola Tesla described the practical application... the radio echo... the magazine “Century”.

(after, of, in, as... as, both... and, that, with, that is).

V. Прочтите текст, назовите ключевое слово текста и его повторы. Выделите в тексте логико-смысловые единства, озаглавьте их:

RADAR

1. The word radar comes from the initial letters of radio detection and ranging. It is a system of detecting distant moving objects and measuring how fast they are travelling and in what direction. Radar works by sending out a beam of short radio waves which is reflected back to the transmitter by any object in its path. The distance of the object can be calculated from the time interval between sending and receiving the beam.

2. Radar was first used in England by Sir Edward Appleton in 1924 to detect electrically-charged layers in the upper atmosphere (ionosphere). It was later developed for military purposes by Sir Robert Watson-Watt. Radar differs from ordinary radio broadcasting in several ways. The transmission is not continuous but consists of a series of high-powered radio pulses, each lasting for ten-millionth of a second. The pulses are sent out in a beam by placing a reflector behind the transmitting aerial. The beam can be sent in any single direction or the whole transmitting system can be rotated so that the beam sweeps a circle (описывает круг). The reflected signal comes back to the transmitter and is displayed on the screen of a cathode ray oscilloscope. Receiving equipment must be very sensitive because the fraction of the pulse reflected back is vary small.

3. Medium-wave broadcasting uses wavelength of several hundred meters. Early radar systems used wavelengths of about ten meters. Even these waves were too long to detect aircraft accurately, and transmitting and receiving aerials for this length of wave were too big to be carried in an aircraft. A new kind of valve, a magnetron, was invented in 1939 which was capable of producing waves only a few centimeters long. It enabled smaller and more sensitive radar to be developed.

(1.800)

VI. Задания к тексту.

Найдите в тексте интернациональные слова и переведите их, не пользуясь словарем. Выпишите из текста многокомпонентные определительные сочетания, переведите их.

Прочтите 1 абзац текста, найдите ответ на следующие волосы:

What is radar? How does radar work?

Прочтите и переведите 2 и 3 абзаци текста.