Question

question 20 of 20 : select the best answer for the question. 20. someone standing in front of a smooth surface from which a sound is reflected may hear a. reflected waves of the same wavelength and less intensity than the original sound source. b. reflected waves of the exact same intensity as the original sound source. c. reflected waves with a smaller wavelength and higher intensity than the original sound. d. reflected waves of a different wavelength from the original sound source. mark for review (will be highlighted on the review page)

Explanation:

1. Recall the properties of sound reflection: The wavelength of a sound wave is determined by its source (since \( v = f\lambda \), and in a given medium, speed \( v \) and frequency \( f \) of the reflected wave from a stationary surface remain the same as the original, so wavelength \( \lambda \) is the same).
2. Analyze intensity: When sound reflects off a smooth surface, some energy is absorbed or scattered, so the reflected wave has less intensity than the original source.
3. Evaluate options:

• Option A: Matches the above (same wavelength, less intensity).
• Option B: Intensity can't be exact same (energy loss), so wrong.
• Option C: Wavelength doesn't decrease, intensity doesn't increase, wrong.
• Option D: Wavelength is same (same frequency, same medium), wrong.

Answer:

A. reflected waves of the same wavelength and less intensity than the original sound source.