Victory for the ACT Student Text 15e

152 • R EADING

The author is most probably leading up to a discussion of some suggestions about how to: A. centralize authority for drug surveillance in the United States. B. centralize authority for drug surveillance among international agencies. Ǥ …‘‘”†‹ƒ–‡ „‡––‡” •Šƒ”‹‰ ‘ˆ information among the drug surveillance agencies. D. eliminate the availability and sale of certain drugs now on the market.

The author makes use of which of the following devices in the passage? Ǥ ‡ϐ‹‹–‹‘ ‘ˆ –‡”• G. Examples H. Analogy Ǥ ‡ϐ‹‹–‹‘ ‘ˆ –‡”• ƒ† ‡šƒ’Ž‡•

7.

8.

Passage II

5 35 Lightning is an electrical discharge of immense proportions. Some 80 percent of lightning occurs within clouds; about 20 percent is cloud-to-ground lightning; and an extremely small percentage is cloud-to-sky lightning. Ž‘—†Ǧ–‘Ǧ‰”‘—† Ž‹‰Š–‹‰ „‡‰‹• ™Š‡ complex meteorological processes cause a tremendous electrostatic charge to build up within a cloud. Typically, the bottom of the cloud is negatively charged. When the charge reaches 50 to 100 million volts, air is no longer an effective insulator, and lightning occurs within the cloud itself. Ten to 30 minutes after the onset of intracloud lightning, negative charges called stepped leaders emerge from the bottom of the cloud, moving toward the earth in 50-meter intervals at speeds of 100 to 200 kilometers per second and creating an ionized channel. As the leaders near the Earth, –Š‡‹” •–”‘‰ ‡Ž‡…–”‹…ϐ‹‡Ž†…ƒ—•‡• •–”‡ƒ‡”• ‘ˆ positively charged ions to develop at the tips of pointed objects that are connected directly or indirectly to the ground. These positively …Šƒ”‰‡† •–”‡ƒ‡”• ϐŽ‘™ —’™ƒ”†Ǥ When the distance, known as the striking distance, between a stepped leader and one of the streamers reaches 30 to 100 meters, the intervening air breaks down completely, and the leader is joined to the Earth via the streamer. Now a pulse of current known as a return stroke ranging from thousands to hundreds of thousands of amperes moves at one tenth to one third the speed of light 40 45 50 55 60 NATURAL SCIENCE: This passage is adapted from a science magazine article that discusses lightning. the streamer emanated and up the ionized channel to the charge center within the cloud. An ionized channel remains in the air and additional negative charges called dart leaders will quickly move down this path resulting in further return strokes. This multiplicity causes –Š‡ ϐŽƒ•Š –‘ ϐŽ‹…‡”Ǥ Š‡ ‡–‹”‡ ‡˜‡– –›’‹…ƒŽŽ› lasts about one second. The return stroke’s extremely high temperature creates the visible lightning and produces thunder by instantly turning moisture into steam. Most direct damage results from the heavy return stroke current because it produces high temperatures in the channel, or from arcing at the point of ground contact. If the lightning current is carried by an enclosed conductor (e.g., within a jacketed cable, through a concrete wall, or beneath a painted surface), entrapped moisture is turned into high-pressure steam that can cause a cable, wall, or painted object to explode. Arcing frequently ignites combustibles. Lightning causes hundreds of millions of dollars in property losses annually and the ƒŒ‘”‹–› ‘ˆ ˆ‘”‡•– ϐ‹”‡•Ǥ ‹‰Š–‹‰ ‹• ƒŽ•‘ –Š‡ leading weather-related killer in the United States, causing 100 to 200 deaths each year. 9. In line 15, the word intracloud most nearly means: A. between clouds. B. within a cloud. Ǥ ˆ”‘…Ž‘—† –‘ •›Ǥ D. from ground to cloud. 10 15 20 25 30

The Cambridge Edge Pay attention to the context when answering Vocabulary items such as #9. Sometimes the context will give you clues as to the correct answer, but you may still need to guess. And sometimes simply reading the context gives you the correct answer.