Reading comprehension puji Astuti Amalia

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Passage 3

Passage 3


A pilot cannot fly a plane by sight alone. In many conditions, such as flying at night and landing in dense


fog, a pilot must use radar, an alternative way of navigating. Since human eyes are not very good at


determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving.


The basic principle of radar is exemplified by what happens when one shouts in a cave. The echo of the


sounds against the walls helps a person determine the size of the cave. With radar, however, the waves


are radio waves instead of sound waves. Radio waves travel at the speed of light, about 300,000 kilometers


in one second. A radar set sends out a short burst of radio waves. Then it receives the echoes produced


when the waves bounce off objects. By determining the time, it takes for the echoes to return to the radar


set, a trained technician can determine the distance between the radar set and other objects. The word


“radar,” in fact, gets its name from the term “radio detection and ranging.” “Ranging” is the term for


detection of the distance between an object and the radar set. Besides being of critical importance to pilots,


radar is essential for air traffic control, tracking ships at sea, and for tracking weather systems and storms.

12. Which of the following would most likely be the topic of the next paragraph?

A. other uses of radar

B. uses of sonar technology

C. other technology used by pilots

D. a history of flying

13. What might be inferred about radar?

A. It takes the place of a radio.

B. It gave birth to the invention of the airplane.

C. It developed from a study of sound waves.

D. It has improved navigational safety.

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