Question 36

The author's primary purpose is to inform the reader about how movement affects sound.

The passage primarily focuses on explaining the Doppler Effect, which describes how the movement of sound-emitting objects influences the frequency and pitch of the sound heard by observers. This scientific explanation is the central theme of the text.

A) To entertain the reader with information about trains and ambulances

While the passage includes examples of trains and ambulances, its primary aim is not entertainment. Instead, it uses these examples to illustrate a scientific concept, making this option incorrect as the main purpose is educational, not entertaining.

B) To inform the reader about avoiding accidents involving trains and ambulances

This option misrepresents the passage's focus. Although trains and ambulances are mentioned, the text does not address safety or accident avoidance. Instead, it aims to explain the Doppler Effect, making this choice inaccurate.

C) To inform the reader about how movement affects sound

This option accurately captures the essence of the passage. The author explains how the movement of sound sources alters the frequency and pitch of the sound waves as experienced by listeners, which is the core subject of the text.

D) To analyze the difference between train and ambulance sounds

This choice is incorrect as the passage does not analyze the sounds of trains and ambulances in detail. It focuses on the concept of the Doppler Effect and does not compare or contrast the sounds of these vehicles, making this option misleading.

Conclusion

The correct answer is option C, as it directly aligns with the passage's objective of elucidating the relationship between movement and sound frequency. The other options either misinterpret the content or divert from the primary focus of explaining a scientific principle, reinforcing that understanding the Doppler Effect is the core takeaway from the text.