 110  measures the ratio of the intensity of a given sound to the standard “zero” sound. The decibel scale ranges from 0 to 130. An intensity of 130 decibels is perceived not only as a sound, but also 5_. The normal range of painlessly audible sounds for the average human ear is about 120 decibels. For forms of life other than ourselves, the range can be quite different. The ordinary sound meter measures the intensity of a given sound, rather than its actual loudness. Under most conditions, however, it is a quite good indicator of loudness. Probably the loudest known noise ever heard by human ears was that of the explosive eruption in August, 1883, of the volcano of Krakatoa in the East Indies. No electronic sound meters, of course, were in existence then, but physicists estimate that the sound at its source must have had an intensity of 190 decibels, 6_. A. and finally measure them. B. since it was heard 3,000 miles away. C. and they have been able to put many of these discoveries to practical use. D. that loud sound is of high intensity. E. as they study mechanical forces. F. as a painful sensation in the ear. G. that the unaided human ear can detect.
A15 — A21 Прочитайте текст и выполните задания А15 — А21, обводя цифру 1, 2, 3 или 4, соответствующую номеру выбранного вами варианта ответа. The Introduction to a New Biography of Gannibal by the Author Alexander Pushkin was not only Russia’s greatest poet, but he was also the great-grandson of an African slave. The slave, whose godfather was Peter the Great, claimed to have royal blood of his own. Certainly his Russian descendants believed that he was an African prince. His descendants have included members as well as close friends of the English royal family. So the legend goes on. 110 |
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