Question

How do sound waves travel by refraction?

Answer 1

Hint: Like any wave, a sound wave doesn't just stop when it reaches the end of the medium or when it encounters an obstacle in its path. Rather, a sound wave will undergo certain behaviors when it encounters the end of the medium or an obstacle. Possible behaviors include reflection off the obstacle, diffraction around the obstacle, and transmission into the obstacle or new medium.

Complete solution:
Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves. So, if the media are changed, the speed of the wave is changed. Thus, waves passing from one medium to another will undergo refraction. Refraction of sound waves is most evident in situations in which the sound wave passes through a medium with gradually varying properties.
The speed of a wave depends on the elastic and inertia properties of the medium through which it travels. When a wave encounters a different medium where the wave speed is different, the wave will change directions. Most often refraction is encountered in a study of optics, with a ray of light incident upon a boundary between two media (air and glass, or air and water, or glass and water). Snell's law relates the directions of the wave before and after it crosses the boundary between the two media.
According to Snell’s law, $\dfrac{{\sin {\theta _1}}}{{{n_1}}} = \dfrac{{\sin {\theta _2}}}{{{n_2}}}$, where ${\theta _1}$ is the angle of the incident ray with normal, ${\theta _2}$ is the angle of refraction with the normal, ${n_1}$ and ${n_2}$ is the refractive index of the medium in which the wave is traveling and that of the medium in which the wave is entering respectively.
Wave changes the amount of energy it possesses after the refraction. Therefore, a sound wave after refraction can be geared with low intensity.

Note: All the waves get refracted when they reach the end of a medium and enter another medium. A sound wave is one of them. In simple words, the refraction of a wave means deflection from a straight path. It happens because the wave always finds a path that is easiest to deliver energy.