The explanation for refraction must involve a change in Warm air you
A. speed.
B. frequency.
C. wavelength.
D. all of these.
Cool air of sound.
The Correct Answer and Explanation is:
Correct Answer: A. speed
Refraction is the bending of a wave as it passes from one medium to another with different properties. For sound waves, refraction occurs when there is a change in the medium’s temperature, such as when sound travels from warm air into cool air or vice versa.
In this context, the key factor that causes refraction of sound waves is the change in the speed of sound in different air temperatures. Sound travels faster in warm air than in cool air because the molecules in warm air are more energetic and move more quickly, allowing sound waves to propagate faster.
When a sound wave passes from warm air to cool air, its speed decreases, causing the wave to bend toward the region of lower speed (cool air). Conversely, when moving from cool air to warm air, the wave bends away from the cooler region due to increased speed. This change in speed results in the refraction of the sound wave.
Let’s consider the other options:
- Frequency (B) of a wave is determined by the source of the sound and does not change as the wave moves between different media.
- Wavelength (C) does change as the speed of the wave changes, but this is a consequence of the change in speed since the frequency remains constant. Wavelength = speed / frequency.
- Therefore, D (all of these) is incorrect because only the speed changes directly due to the medium; frequency remains constant, and wavelength changes only as a result.
Thus, option A (speed) is the correct and most direct explanation for the refraction of sound as it passes between warm and cool air. This principle is also responsible for real-life phenomena like sound being clearer at night or early morning, when temperature gradients in the atmosphere are more pronounced.
