Question 11

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

The essay primarily aims to explain the Doppler Effect, specifically how the movement of objects like trains and ambulances influences the frequency and pitch of sound. By discussing these examples, the author illustrates the scientific principles behind the phenomenon.

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

While the examples of trains and ambulances may be engaging, the author's main goal is not to entertain but to educate the reader about a scientific concept. The focus is on explaining the Doppler Effect rather than simply providing interesting anecdotes.

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

This option misinterprets the author's intent. Although awareness of sound changes can be relevant to safety, the essay does not provide guidance or advice on accident avoidance. Instead, it focuses on the scientific explanation of sound dynamics due to movement.

C) To inform the reader about how movement affects sound

This choice accurately reflects the author’s objective. The discussion centers on the relationship between the movement of objects and the resulting changes in sound frequency and pitch, effectively illustrating the Doppler Effect.

D) To analyze the difference between train and ambulance sounds

This option is incorrect as the essay does not delve into a comparative analysis of the sounds themselves. Instead, it uses these examples to explain a broader concept regarding how sound behaves as objects move, rather than focusing on the sounds of the individual vehicles.

Conclusion

The correct answer, C, is definitively right because it encapsulates the essence of the discussion around the Doppler Effect and how movement affects sound. Other options either misinterpret the author's intent or focus on unrelated aspects, failing to capture the primary educational purpose of the essay.