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
Explanation:
Refraction refers to the bending of a wave as it passes from one medium to another in which its speed changes. This concept is commonly associated with light, but it also applies to sound waves and other types of waves such as water and seismic waves.
When a sound wave travels from one medium to another—say, from warm air to cool air—its speed changes due to the difference in the density and temperature of the air. Warmer air is less dense and allows sound to travel faster, while cooler air is denser and causes sound to travel slower. The bending or redirection of the wave that occurs as a result of this change in speed is what we call refraction.
The most critical factor in refraction is the change in speed. Although the wavelength of the sound wave may also change as a result of the speed change, the frequency remains constant. This is important: the source of the wave determines its frequency, and changing the medium does not affect this frequency. However, since speed $v$ is related to frequency $f$ and wavelength $\lambda$ by the equation:
$$
v = f \times \lambda
$$
If the speed $v$ changes and the frequency $f$ remains constant, then the wavelength $\lambda$ must change accordingly. This explains why wavelength changes too—but only as a consequence of the speed change, not as an independent factor of refraction.
So while the wavelength may also change, and the frequency stays the same, the root cause of refraction is the change in the speed of the wave as it moves through different media. Therefore, the correct answer is A. speed—not “all of these.”
Summary:
- Refraction occurs because the speed of the wave changes.
- Frequency remains constant.
- Wavelength changes only as a result of the speed change.
- Therefore, speed is the key factor responsible for refraction.
